That Stephen was a Jew is unquestionable, and he probably was a Hellenist of the Dispersion, who spoke Greek. The name Stephen is Greek, Stephanos, and signifies "crown". The circumstances of his conversion to Christianity are not known.
The Apostles assembled the faithful and told them that they could not relinquish the duties of preaching and prayer to attend to the care of tables; and recommended them to choose seven men of good character, full of the Holy Ghost and wisdom, who might superintend that business. The people chose Stephen, "a man full of faith and of the Holy Ghost", and Philip, Prochorus, Nicanor, Timon, Parmenas, and Nicholas. These seven were presented to the Apostles, who, praying, imposed hands upon them, and so ordained them the first deacons.
Stephen spoke with such wisdom and spirit that his hearers were unable to resist him, and a plot was laid by the elders of certain synagogues in Jerusalem. The main point urged against him was that he affirmed that the temple would be destroyed, that the Mosaic traditions were but shadows and types no longer acceptable to God, Jesus of Nazareth having put an end to them.
Stephen was allowed to speak and in a long defense laid out in Acts 7:2-53, he showed that Abraham, the father and founder of their nation, was justified and received the greatest favours of God in a foreign land; that Moses was commanded to set up a Temple, but it was not to be imagined that God was confined in houses made by hands: the temple and the Mosaic law were temporary, and were to give place when God introduced more excellent institutions by sending the Messiah himself. He ended with a stinging rebuke: "You stiff-necked and uncircumcised in hearts and ears, you always resist the Holy Spirit; as your fathers did, so do you also. Which of the prophets have not your fathers persecuted? And they have slain them who foretold the coming of the Just One, of whom you have been now the betrayers and murderers: who have received the law by the disposition of angels, and have not kept it."
The whole assembly raged at Stephen, but he, being full of the Holy Spirit and looking up steadfastly to the heavens, saw them opened and beheld the glory of God and the Saviour standing at the right hand of the Father. And he said, "Behold, I see the heavens opened, and the Son of Man standing on the right hand of God". And they, crying out with a loud voice, stopped their ears and with one accord ran violently upon him. And, casting him forth without the city, they stoned him; and the witnesses laid down their garments at the feet of a young man whose name was Saul. And they stoned Stephen, invoking and saying, "Lord Jesus, receive my spirit". And falling on his knees, he cried with a loud voice, saying, "Lord, lay not this sin to their charge". And when he had said this he fell asleep in the Lord. , (Derived from Butler's Lives of the Saints, revised edition, Copyright Burns and Oates, 1991)