This is in Anita Rai's biography of the Prophet (pbuh). One of the worst books I've read. She notes that Abi Bakr and Umar went to a sorcerer/fortune teller who told them that a man would spread a religion in Arabia and that they would be his successors. From that point on they kept an eye out for prophets and realised Muhammad (pbuh) was the one and joined him early on.
It paints a picture that they were power hungry and became Muslim only for the Caliphate. Only an idiot however would say that Abu Bakr and Umar lived in luxury or were wealthy rulers.
The truth is, according to one narration he went to Khatijah's uncle Waraka'-b-Naufal and then decided to accept Islam.
Abu Bakr narrates, " and I, had not
heard before that of a prophet expected who was to be sent." He
adds. " Then I went out to Waraka'-b-Naufal* and he was one who con.
stantly watched the heavens and muttered frequently to himself and I
stopped him and related to him the circumstance. He said " Tea—O
!sou of my brother, I am skilled in the scriptures and in knowledge ; know,
that this prophet, he whom men await, shall be by descent of the most
noble of the Arabs. I am likewise skilled in genealogy, and thy tribe is
by descent, the most noble among the Arabs." I said. " O uncle, and
what will the prophet say ?" He replied, " he shall speak that which
hath been said to him, and know, that he shall not oppress nor be oppress- •
ed nor desire you to oppress each other." Therefore when the Apostle of
God was sent, I believed in him and testified to him."
As for wealth he has 40,000 dirhams before Islam, and it decline after that.
Ibn A'sakir from Ayesha with- different authorities,
and from U'rwah-b-uz-Zubayr,,that on the day when Abu Bakr was
converted, he had forty thousand dinars—and according to another reading,
forty thousand dirhams, and he spent them upon the Apostle of God.
Abu Sa'id al Aa'rdbi records on the authority of Ibn O'mar, that on
the day when Abu Bakr was converted, he had in his house forty thousand
dirhams, and when he set out for Medina at the time of the Tlight, he had
no more than five thousand, all of which he spent upon the manumission
of slaves, and in aid of Islam. And Ibn A'sikiv on that of Ayesha, that
Abu Bakr gave freedom to seven slaves all of whom had suffered persecution
for the sake of God.
As for fortune, yes Abi Bakr bet his whole wealth against the pagans of Mecca by supporting the Romans against the Persians. When he told the Prophet (pbuh), the Prophet (pbuh) told him to double his bet.