No need to try harder, it's not issue of PHD.
"O you who have believed, obey Allah and obey the Messenger and ALL SO OBEY those in authority among you"
What's difficult to understand here apart from someone being third in line in authority. And Muhammad s.a.w introduced them. Why do I need to try harder? You're the one who needs to save Saqifa and to protect those who kicked it off.
Hmm... let us see once again:يَا أَيُّهَا الَّذِينَ آمَنُوا
أَطِيعُوا اللَّهَ وَأَطِيعُوا الرَّسُولَ وَأُولِي الْأَمْرِ مِنْكُمْ ۖ فَإِنْ تَنَازَعْتُمْ فِي شَيْءٍ فَرُدُّوهُ إِلَى اللَّهِ وَالرَّسُولِ إِنْ كُنْتُمْ
تُؤْمِنُونَ بِاللَّهِ وَالْيَوْمِ الْآخِرِ ۚ ذَٰلِكَ خَيْرٌ وَأَحْسَنُ تَأْوِيلًا
(Sahih International)
O you who have believed,
obey Allah and obey the Messenger and those in authority among you . And if you disagree over anything, refer it to Allah and the Messenger, if you should
believe in Allah and the Last Day. That is the best [way] and best in result.
-Sura An-Nisa', Ayah 59
Hmm... those in red above STILL doesn't sound like the obligation to believe in imamah at all.
Obligation to "believe in something" should sound like those in blue:لَيْسَ الْبِرَّ أَنْ تُوَلُّوا وُجُوهَكُمْ قِبَلَ الْمَشْرِقِ وَالْمَغْرِبِ وَلَٰكِنَّ الْبِرَّ مَنْ
آمَنَ بِاللَّهِ وَالْيَوْمِ الْآخِرِ
وَالْمَلَائِكَةِ وَالْكِتَابِ وَالنَّبِيِّينَ (Sahih International)
Righteousness is not that you turn your faces toward the east or the west, but [true] righteousness is [in] one who
believes in Allah , the Last Day, the angels, the Book, and the prophets.-Sura Al-Baqarah, Ayah 177
آمَنَ الرَّسُولُ بِمَا أُنْزِلَ إِلَيْهِ مِنْ رَبِّهِ وَالْمُؤْمِنُونَ ۚ كُلٌّ
آمَنَ بِاللَّهِ وَمَلَائِكَتِهِ وَكُتُبِهِ وَرُسُلِهِ لَا نُفَرِّقُ بَيْنَ أَحَدٍ مِنْ رُسُلِهِ ۚ وَقَالُوا سَمِعْنَا وَأَطَعْنَا ۖ غُفْرَانَكَ رَبَّنَا وَإِلَيْكَ الْمَصِيرُ
(Sahih International)
The Messenger has believed in what was revealed to him from his Lord, and [so have] the believers. All of them have
believed in Allah and His angels and His books and His messengers,[saying], "We make no distinction between any of His messengers." And they say, "We hear and we obey. [We seek] Your forgiveness, our Lord, and to You is the [final] destination."
-Sura Al-Baqarah, Ayah 285
يَا أَيُّهَا الَّذِينَ آمَنُوا
آمِنُوا بِاللَّهِ وَرَسُولِهِ وَالْكِتَابِ الَّذِي نَزَّلَ عَلَىٰ رَسُولِهِ وَالْكِتَابِ الَّذِي أَنْزَلَ مِنْ قَبْلُ ۚ وَمَنْ يَكْفُرْ بِاللَّهِ وَمَلَائِكَتِهِ وَكُتُبِهِ وَرُسُلِهِ وَالْيَوْمِ الْآخِرِ فَقَدْ ضَلَّ ضَلَالًا بَعِيدًا
(Sahih International)
O you who have believed,
believe in Allah and His Messenger and the Book that He sent down upon His Messenger and the Scripture which He sent down before. And whoever disbelieves in Allah , His angels, His books, His messengers, and the Last Day has certainly gone far astray.
-Sura An-Nisa', Ayah 136
A bit more harder, please, and without tahreef too!