The alteration of Stephen’s face was an act of God to make it shine. The purpose for doing so seems to be along the lines of what took place with Moses—just as the shining of Moses’ face indicated to Israel that Moses spoke on behalf of God because he spoke directly to Him, so also the shining of Stephen’s face indicated to Israel that Stephen spoke on behalf of God as well.
What did it mean that Stephen’s “face was like the face of an angel” (Acts 6:15), and why did it look this way?
We first meet Stephen as a deacon, “a man full of faith and of the Holy Spirit” (Acts 6:5). He was appointed to coordinate meals for widows (cf. Acts 6:1–7), but he was also an evangelist. He was “full of grace and power…doing great wonders and signs among the people” (Acts 6:8). This grace and power go together and describe the boldness of Stephen and God’s confirmation of his witness through wonders and signs (cf. Acts 4:33). The mention of grace likely implies that God extended His saving grace to others through the witness of Stephen (cf. Acts 11:23).
When opposed by others in his endeavors, Stephen refuted his aggressors, and “they could not withstand the wisdom and the Spirit with which he was speaking” (Acts 6:10; cf. Luke 21:15). So, they lied, stirred up the people, arrested him, falsely tried him, and eventually stoned him, making him the first martyr of the church (Acts 6:8–7:60). His story has echoes of the final days of Jesus.
At the outset of his trial, as Stephen prepared to speak once again full of wisdom and the Spirit, the Bible records what everyone saw when looking at Stephen: “And gazing at him, all who sat in the council saw that his face was like the face of an angel” (Acts 6:15). What did this angel-like face mean?
In answering this question, we recall that angels can be brilliant, shining creatures. Remember the angel at Jesus’ empty tomb—“His appearance was like lightning, and his clothing white as snow” (Matthew 28:3). If Daniel 10:6 describes an angel (some say the preincarnate Son of God), “his face” is “like the appearance of lightning.” If Revelation 10:1 describes an angel (and again, some say the now-incarnate Son of God), “his face was like the sun.” The angelic creatures who guided the heavenly chariot in Ezekiel’s vision had four faces each, and as to their faces and even their whole beings, “their appearance was like burning coals of fire, like the appearance of torches moving to and fro among the living creatures. And the fire was bright, and out of the fire went forth lightning” (Ezekiel 1:13). The point of similarity between the face of Stephen and the face of an angel was most likely this—it was a shining face.