A Christian monk on seeing the Prophet (s.a.w.a.) prophesied about Ameerul Momineen (a.s.) –
he will be the first to believe in the prophethood of Muhammad. I have read in divine scriptures that he will be the Prophets legatee. He will be the chief of the Arabs, a divine scholar and Zulqarnain of the last prophet; who will wage holy wars. His name in the high abodes is Ali. On Judgment Day his rank will be the highest after the rank of Muhammad. Angels call him a victorious brave light. He will be victorious wherever he will go. Among the companions of your prophet, he is most well known than the sun in the sky.
Hayaat al-Quloob v 2 chap 4