Ye stiffnecked and uncircumcised in heart and ears, ye do always resist the Holy Ghost: as your fathers did, so do ye. Which of the prophets have not your fathers persecuted? and they have slain them which shewed before of the coming of the Just One; of whom ye have been now the betrayers and murderers: Who have received the law by the disposition of angels, and have not kept it. When they heard these things, they were cut to the heart, and they gnashed on him with their teeth. But he, being full of the Holy Ghost, looked up stedfastly into heaven, and saw the glory of God, and Jesus standing on the right hand of God, And said, Behold, I see the heavens opened, and the Son of man standing on the right hand of God. Then they cried out with a loud voice, and stopped their ears, and ran upon him with one accord, And cast him out of the city, and stoned him: and the witnesses laid down their clothes at a young man’s feet, whose name was Saul. And they stoned Stephen, calling upon God, and saying, Lord Jesus, receive my spirit. ~ Acts 7:51-59

Stephen in Acts 7, and John on the isle of Patmos (Revelation 1:13; 14:14) are the only references I know of in the NT where Jesus is referred to as the Son of man by someone other than himself. Here Stephen, before an angry Sanhedrin, sees Jesus (the Son of man) standing on the right hand of God. The Sanhedrin was the supreme council and tribunal of the Jews, led by the High Priest.

Stephen’s proclamation was the ultimate condemnation to these wicked leaders. They all knew what Stephen meant by declaring that he was seeing the Son of man standing on the right hand of God. The One they hated and had put to death by wicked hands and deceit, was God’s appointed ruler, judge, and King. They knew the prophecy given by Daniel.

I saw in the night visions, and, behold, one like the Son of man came with the clouds of heaven, and came to the Ancient of days, and they brought him near before him. And there was given him dominion, and glory, and a kingdom, that all people, nations, and languages, should serve him: his dominion is an everlasting dominion, which shall not pass away, and his kingdom that which shall not be destroyed. ~ Daniel 7:13-14

Stephen seeing the Son of man meant that Jesus, the Messiah was now enthroned with all rule and authority under him. Stephen’s testimony aligns with what John saw in the book of the Revelation.

And in the midst of the seven candlesticks one like unto the Son of man, clothed with a garment down to the foot, and girt about the paps with a golden girdle. ~ Revelation 1:13

And I looked, and behold a white cloud, and upon the cloud one sat like unto the Son of man, having on his head a golden crown, and in his hand a sharp sickle. ~ Revelation 14:14

I don’t think many of us truly appreciate what we are reading, when we read the words of Jesus, declaring himself to be the Son of man. Every time Jesus referred to himself as the Son of man, he was claiming to be the Messiah and the righteous ruler whom Daniel saw in the presence of the Ancient of Days.