Is the impression it gives clear or unclear?
Sunnis want people to believe that the verse 42:23 is unclear and can mean many things. This is there strategy whenever it comes to a verse that manifests the position of the Imams. The first argument I would make is that since this is the wage of the message, whatever God said, he said it in a clear enough manner, that the meaning implied is known and is not unclear. Sunnis admit it can mean family of Mohammad as that is one of the possibilities they give in the possible meanings in their commentaries of Quran. However they argue that it can mean other things like the kinship between Quraysh and Prophet. A newer outlook because people are aware of the various other wage verses is that it can also mean closeness to God. However I argue that there is only one meaning that is the clear impression it gives. And the first impression is the near relatives of Mohammad. Sunnis want to make it as if there is no first clear impression and that various meanings are on the table. I argue for something this important, for the wage of the message, God would definitely give one meaning that is manifest and clear, while the others would be people being obtuse. Something this important in Quran, which being grateful to the message is summarized in, would not be something ambiguous.
Can it mean Qurayshi kinship?
Love of Qurayshi kinship is unrelated to the message of Islam and showing gratitude for it. Moreover other verses show the wage is in fact a reminder to the worlds and is taking a path to God. Therefore it doesn't make sense it refers to Qurayshi kinship. The interpretation the Prophet didn't ask a wage also goes against the norms of language, but if it the exception refers to all that he asks, then again, he doesn't simply ask Quraysh to love kinship between him and them, he is asking a lot more. That and the obvious impression is that the exception is towards the wage being asked, that he asks no wage, but that.
Can it mean closeness to God?
It goes against the norm of language to assume it means "closeness". Closeness can mean a lot of things, for example, it can refer to family closeness, it can refer to closeness between believers, it can refer to many things, and hence it would be ambiguous while we need to know what the wage is commanding. People can say since the other verses say it means taking a path to God, it means obviously love of closeness to God. We have to investigate is love of closeness to God the path towards God?
If it said "love of God", I would understand that being a path to God. Since love of God includes loving humans and the light within them, it includes taking care of yourself for his sake, and fearing the hell fire for his sake, and loving the Prophet for God's sake.
But closeness to God is not the same as saying love of God. It's love of being close to God, which is love a the reward of God and being near to him. This doesn't include loving God for his sake, but would make you love God for the sake of attaining nearness to him. You wouldn't love people for the sake of the light of God within them, you would love them for the sake of attaining nearness to God. This is problematic for many reasons.
Moreover, people can want to attain nearness of God, but if they are not sincere to his obedience, respect his greatness, and love submitting to him, this has many problems.
That is why people ought to strive for God's sake, and not simply out of love of attaining nearness to him, which is important of course. Of course those who want the next world and his nearness, they ought to realize that path that God wants people to walk upon, and God will guide them to that path. Wanting nearness of God however is not the path.
Is love of the family of Mohammad a full description of the path to God?
Since the core of the chosen ones of God is love of God and love for his sake, loving them automatically makes one love God. As their path includes unifying God and testifying to his absolute glory and uniqueness, we ought to love that path. Now when it comes to loving God, it can also be seen that whatever light of God we come to know of, they have as well. Whatever degree of knowledge of God it means they unite such glory and beauty in their innermost souls. The only difference is that we know God has it absolutely but we can never recognize that absolute light. Hence whatever finite degree of knowledge of God in the sense of witnessing beauty, praise, and glory, then that unites in the holy souls of Ali and Fatima and the Imams from their offspring. Aside from that, loving them means loving that very light connected to God, and if we love that light, we love creation in so far as they as blessed by those blessings found in Ahlulbayt and we distance ourselves from the darkness and evil in so far as it's opposite to that light. If we love Ahlulbayt with sincerity, they become the measurement by which we respect and love others. Of course, we have to honor that very light rights when it appears in form of father, or a son, or sister or mother or daughter or aunt or uncle, etc, it takes on different forms and demands different relationship. Loving the path of Taqwa and vision of God's beauty, is the essence of loving Ahlulbayt (as), and this includes loving others for the sake of God. At the same time, when it comes to the path of submission to God, it makes one disbelieve in the Taghut since they are anti-chosen ones' authority. It makes one love that submission to God through his chosen ones. It makes one appreciate God's guidance with his chosen ones.
This is because the light of Ahlulbayt [as] is from God. This is because Ahlulbayt [as] unite all light in creation. This because they are that very light of Mohammad [pbuh&hf]. This is because they unite all virtues of the Prophets [as] and loving them includes loving the Prophets [as]. This is because all good is found in them. This is because whatever good we can do, that goodness, the good act, is found in them and recognizing their position would make us love true goodness, true virtue, the true path.
This because all creation blessings is united in their holy souls and loving them means to love and appreciate all blessed goodness and beauty in creation.
This also because they unite all pathways towards God, and are the straight path.
God's Name and his path, always has a designation.
Aside from that, the fact is, God's Name and religion always has a designation, a door to enter by and submit through.
For example, Jesus was the door people had to enter by.
There is always a designation. If the family of Mohammad was not that designation, then it would be only the Prophet. The Prophet would be that designated path. However, the fact is, the submission to God and submission to the Prophet of God, has been designated to them.
Therefore to submit to God and submit to the Prophet's call, once has to follow them and love them. Loving them means one is attached to their light and follows them inwardly and not just outwardly. It means to love the inward way and not simply their outer actions.
In fact it is clear when we think about how much Quran emphasized on entering the door that God has told people to enter by, whether it was Adam, or Noah or Abraham or the family of Abraham, or the Prophets of Bani-Israel, we have to enter the door in a spirit of humbleness and submission to God.
We acknowledge the position his chosen friends have and submit through them to God. This wisdom is emphasized through out the Quran.
Everyone can claim to love closeness to God
The wage verses would be ambiguous in describing the path to God. Everyone can claim to love closeness to God and it does nothing to separate misguidance from guidance. Given how much wage verses are emphasized, this goes against the eloquence of Quran. Of course Quran does command towards goodness in general, but to say something to the effect "be good" without designating that path of being good and distinguishing the path of error and evil from that of good and faith, would go against the eloquence expected of God. He constantly reminds of the wage in all together 9 verses directly, and there is other verses indirectly mentioning other Prophets didn't ask a wage. Which will bring the next point.
Why didn't the other Prophets ask a wage?
If the path was always love of closeness to God, then why didn't all Prophets ask a wage? Think about it. Why didn't they all say I ask you nothing in return of this message except the love of closeness to God? The reason being was the Prophets themselves were that path to God during that time. After them, Prophets would succeed them in which their message also was asking them to follow the Prophets. It would go against eloquence to say "I ask you nothing in return except to follow me" or "to love me". That is against all eloquence. It would make them appear to be power hungry in front of their people. The same is true of saying "but to follow the Prophets" when it's understood they are one of them.
However, the Quran in it's eloquent manifestation, showed, that, is clarifying "the wage is for ourselves", while that is not needed if it was simply love of closeness to God. It emphasizes the wage is for our benefit and that in fact is taking a path to God.
It also introduces the concept of chosen families, which then, would make us understand, his true near relatives and near kin, is not normal people. The meaning of family takes on a higher metaphorical meaning, and is emphasized to be family in a sense others are not included in that definition.
If the Prophet said 'but to follow me' it would give the impression, that Mohammad didn't really want anything in return but to be followed. This can be interpreted both in positive but given the context of the wage of all Prophets, it would go against the reason why none of them asked, and the reason is obvious, is that it can give impression to people of bad mindset, that the Prophet is power hungry and wants to be followed in that sense.
It seems a similar thing can be assumed about his family, that he cares about his near relatives, that he wants nothing in return but to love them, but we see clarification in Quran that in fact it is a reminder to the worlds, and is a path towards God, and is being asked for our sake, while his reward is with God the lord of the worlds and the concept of chosen families in Quran.
The latter statement shows this being asked by Prophet on behalf of God as well, that to appreciate the message of God, the gift of the Quran and Sunnah, we ought to love the family of Mohammad.
That without their love, we would not appreciate the message of God nor show gratefulness to God for sending us Mohammad.
Explanation by the Prophet
Clarification by the Prophet would be essential regarding this verse, and the only clarification attributed to the Prophet about it, is about it being about the family of Mohammad. Not one hadith exists stating it's about closeness to God for example. There is a hadith that Ibn Abbas says it's Qurayshi kinship but aside that being refuted, it wasn't an explanation attributed to the Prophet. And it was arguing with someone who expressed it being the family of Mohammad and telling him he was being hasty. Even in that hadith, we see that, the first impression and obvious one is the family of Mohammad. The closeness to God was not even mentioned as a possibility in that hadith because how far off in language it is to assume that. "love of the kinship" is also far off but who ever fabricated that to Ibn Abbas, that is the best he can think of. However as we would expect an explanation by those who want to follow the truth regarding the Quran and seek an explanation from it from the Prophet, it is sufficient to point out the only ahadith attributed to the Prophet about it show that it means his family.
Context of wage verses.
The first time you will come across a wage verse in Quran reading it chronologically would be in Surah 6. And it's after emphasizing on the Prophets, and they were chosen from one another's offspring and brothers, and that after it emphasizes on Mohammad [pbuh&hf] to follow their guidance and take guidance from their guidance and be guided by their example, it tells us that wage is but a reminder to the nations.
The impression with "al-Qurba" surely then is that they are similarly to be taken guidance from by people, that in them unites the guidance of the Prophets including that last one.
We see also a reminder in Suratal Yusuf which has a theme of chosen ones and inheritance of chosen family members from one another in guiding their community. It has also other relationship with themes in that Surah.
The point is if we study the context of all these Surahs, they are best explained and point to the emphasis being that the family of Mohammad is a family of chosen people to be taken as examples and guides to the nations.
That love of them is a reminder and call to the straight path. That people are not oblivious or need in being told to love closeness of God but rather people always show unwillingness to enter the door God has opened for them.
The flow of the Surah, the place of it in the Surah, and the verses surrounding it, all manifests the theme of the wage being love of the family of Mohammad. That much of the Quran is saying, these Surahs intertwine with one another and point to why God has told our Prophet to ask this wage, that no doubt, all eloquence lies in it's apparent meaning and that verse 42:23 would not be ambiguous. It lies that these Surahs are explaining to humanity, this is what God has in fact revealed to Noahh, and Abraham and Moses and Jesus, and the Prophets, that he chooses for himself who he pleases and guides to himself who he turns to him frequently. That this path of designation of door of submission is now to Ali. That his family and him are that the submission to the Quran.
That these exalted souls inherit that spirit that he inspired Mohammad by and continue to guide humanity after him.
Study the context of these verses and you will see an entire theme is about this issue and it explains and manifests how Quran has an argument, has a message that is not circular, that is not simply saying "there was plenty of the Prophets in the past, so why not believe in the last one?", but that there is a design in God's way of guidance, in the world, a plan, a majestic plan he has, that can be reasoned through and seen in all holy books in their interior logic, despite how corrupted they are now (with exception of Quran).
That no doubt if you acknowledge the way of the past, you ought to acknowledge the perfection of God's religion and plan. There is a theme in all this, and the emphasis on the wage of the message no doubt is about tying the past with the present and future.