Actually servant17,
This thread is on early sources of Islam not the Baha’i. I’m still waiting on Tony to talk about the Shia as he said he’d expand on it. If your intent is to discuss the Baha’i please know we mean no disrespect but you seem to be in the wrong thread. Please confine the Baha’i subject matter to a thread on the Baha’i not Islam.
Hello again gmcbroom, I am sorry I have not got back to this, I am currently moving life between countries, so have limit time and internet.
I have Read that Muhammad did indicate that Ali who was as the cousin and then the son-in-law of the Islamic prophet Muhammad, would be His Successor much like Jesus indicated that upon Peter would build Hid church.
He was 10 years old when he Accepted Muhammad and the fist hint that was to succeed Muhummad happened around the age of 13
“Muhammad invited people to Islam in secret for three years before he started inviting them publicly. When he was commanded to invite his closer relatives to come to Islam he gathered the Banu Hashim clan in a ceremony. According to al-Tabari, Ibn Athir and Abu al-Fida, Muhammad announced at invitational events that whoever assisted him in his invitation would become his brother, trustee and successor. Only Ali, who was thirteen or fourteen years old, stepped forward to help him. This invitation was repeated three times, but Ali was the only person who answered Muhammad. Recognising Ali’s continual and singular response to his call, Muhammad declared that Ali was his brother, inheritor and vice-regent and people must obey him. Most of the adults present were uncles of Ali and Muhammad, and Abu Lahab laughed at them and declared to Abu Talib that he must bow down to his own son, as Ali was now his Emir”.
There were other events where Muhammad talked about Ali being the Peter of the Muslim revelation.
It was His youth that led to the rejection of Him by the Older Believers after Muhammad passed on.
I would think that there was no one that knew the Message of Muhammad better, then there was this;
"Ali compiled a complete version of the Quran, mus’haf,six months after the death of Muhammad. The volume was completed and carried by camel to show to other people of Medina. The order of this mus’haf differed from that which was gathered later during the Uthmanic era. This book was rejected by several people when he showed it to them. Despite this, Ali made no resistance against standardised mus’haf.
Will take a lot of time to take in all this information, time I have to give away to other tasks at this time

This link has a lot!
en.wikipedia.org/wiki/Ali#cite_ref-10 of course there will be many other sources as well.
It was this line of 12 Imams that said to be the rightful successors of Muhammad and the 12th died out in the year 260ah which there is a prophecy in the Koran that 1000 years would then pass before the promised return. Making the year 1260AH, which is the year 1844AD,
Sorry I have to let this go for a while, so much to do.
God bless and always be happy Regards Tony