That in the dispensation of the fulness of times He might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in Him -Ephesians 1:10

In the fulness of time, our Lord Jesus Christ left the glories of heaven, and took upon Him our nature. We know so little of what the word “heaven” means that we cannot adequately appreciate the tremendous sacrifice that the Son of God must have made in order to become the Son of Mary. The holy angels could understand far better than we can what their Lord and ours gave up when He renounced the royalties of heaven, and all the honour and glory which rightly belonged to Him as the Son of the Highest, and left His throne and crown above to be born as the Babe of an earthly mother, yet even to them there were mysteries about His incarnation which they could not fathom; and as they followed the footprints of the Son of man on His wondrous way from the manger to the cross and to the tomb, they must often have been in that most suggestive attitude of which Peter wrote, “which things the angels desire to look into.” To us, the incarnation of Christ is one of the greatest marvels in the history of the universe, and we say, with Paul, “Without controversy great is the mystery of godliness: God was manifest in the flesh.” The omnipotent Creator took the nature of a creature into indissoluble union with his divine nature; and, marvel of marvels, that creature was man.

O glorious Bridegroom of our hearts, there never was any other love like Thine! That the eternal Son of God should leave His Father’s side, and stoop so low as to become one with His chosen people, so that Paul could truly write, “We are members of His body, of His flesh, and of His bones, is such a wonder of condescending grace and mercy that we can only exclaim again and again, “Behold how He loved us!”~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/3228.cfm