One of the four hanifs (who were montheists) mentioned by Ibn Ishaq. The others being Waraqa b. Naufal, Ubaydullah b. Jash and `Uthman b. Al-Huwayrith, who all became Christians. Zaid b. Amr did not become a Muslim or Christian, but forsook paganism and worship one God in the Ka'aba, and was reproached by his pagan uncle. He used to taunt the pagan Quraysh by:
"O tribe of Quraish, by Him in whose hand is the soul of Zaid b. Amar, not one of you has attained unto the religion of Abraham except myself." (Ibn Ishaq, The Life of Muhammad, tr. Guillaume, pp. 99-100).Despite his taunt, however, he was still searching, for he wrote:
"O God, if I knew which manner is most pleasing to Thee, I should worship Thee in it; but I know it not." (ibid).Ibn Ishaq goes on to relate that someone ask the prophet to pray for Zaid, which he did and said:
"Yes, for verily he shall be raised up by himself as a religious sect." (Ibn Ishaq, as quoted by W. Tisdal, Original Source of the Quran, SPCK, 1911, pp. 266-267).It is not clear, however, what sect Muhammad was refering to, and history does not seem to record any sect named after or raised after him.