John 17:4 [RSV]
I glorified Thee on earth, having accomplished the work which Thou gavest me to do.
The Lord Jesus has been manifesting God’s glory as He has come into the world, and as He has done the work that the Father gave Him to do. But, of course, that was a veiled glory. You will notice that the Lord does not divest Himself of His glory when He comes into His flesh, and is born in Bethlehem. He veils His glory. Charles Wesley is therefore right when he sings, ‘Veiled in flesh the Godhead see.’ But in His flesh our Lord manifested the glory of God in a veiled way. He does so because, of course, men in the world could not have stood it, if the glory of God had not been veiled. It would have been impossible for them to look upon Him; and sometimes it seems as if that is almost beginning to happen, and the veil is wearing very thin. At the transfiguration, for example, when our Lord is metamorphosed before them, they bow before Him shining with glory.
You get it in some other places too. It is very significant, I believe, that the men coming into the garden to take Jesus, say, ‘We seek Jesus of Nazareth,’ and He confronts them and says, ‘I am He.’ Now do you remember what you read after that? ‘They fell back…’ Why do you think these men fell back? Not with fear – they were with some soldiers to take Him away. No; I think it was because when He declared Himself ‘I AM’ something of the glory began to break through. But lustrous and blinding though that glory was to men, it was the glory of His humiliation; and that was as nothing compared with the light inaccessible which was His in eternity. It was veiled in the flesh of Jesus in the world. – Eric J. Alexander: Our Lord’s Consecration and Intercession [iv], 1973
– Matthew Henry Commentary