As a Gentile, the centurion was unlikely to know about the expectations regarding the coming of the Messiah. He would, however, be aware that the Roman Caesar Augustus also used the title son of god
to refer to himself. The meaning was that he is the person on earth in whom the deities were pleased and his authority was divine. Having seen the sky darkened for three hours and the way in which Jesus has responded to his accusers, the centurion has somehow come to realize that the true Son of God is Jesus the Christ.
In the Old Testament, the phrase son of God
is used for angels (Genesis 6:2; Daniel 3:25), Israel (Exodus 4:22–23; Malachi 2:10) and the king (2 Samuel 7:14; Psalm 2:7). All specify a unique relationship to God. The early church used this term to describe the uniqueness of Jesus’ intimacy with his Father, tantamount in many ways to a declaration of his divinity. When this expression is used in Mark by the evil spirits (Mark 3:11; Mark 5:7) and the centurion at the cross (Mark 15:39), it emphasizes the divinity of Jesus.
Thus the centurion realizes that Jesus, not the Caesar of Rome, is divine.
39 And when the centurion, who stood facing him, saw that in this way he breathed his last, he said, “Truly this man was the Son of God!”