Hebrews 1 declares to us that Christ is divine. He is God. He is the exact representation of God's nature. He upholds all things by His power. The Father says of the Son "Thy throne, O God, is forever and ever."
Hebrews 2 declares to us that Christ is also man. He partook of flesh and blood. Christ was the God/man - 100% God and 100% man. The fancy theological term is the hypostatic union.
The Westminster Confession of Faith puts it like this: "The Son of God, the second person of the Trinity, being very and eternal God, of one substance and equal with the Father, did, when the fulness of time was come, take upon Him man's nature, with all the essential properties, and common infirmities thereof, yet without sin; being conceived by the power of the Holy Ghost, in the womb of the virgin Mary, of her substance. So that two whole, perfect, and distinct natures, the Godhead and the manhood, were inseperably joined together in one person, without conversion, composition, or confusion. Which person is very God, and very man, yet one Christ, the only Mediator between God and man."
There was a time in my early days as a Christian when I simply took that as fact. It was good information to have if I found myself in the midst of a Bible/theological trivia game. "Hypostatic union" is a rather impressive phrase!
Yet the two natures of Christ are much more than trivia. They are the heart and soul of our salvation. It is who the Lord Jesus HAD to be if He was to save us. The hypostatic union is at the heart of our redemption.
We are sinners by nature and the just wages of that sinful nature is death (Rom 3:23, 6:23). Having fallen in Adam we are covered and condemned with the guilt and pollution of sin. In him as our federal head, we are born dying and apart from some miraculous intervention we will be always dying but never fully dead throughout eternity.
Enter Christ - the God/man. Enter the one and only hope for sinners. "For as in Adam all die, so also in Christ all shall be made alive." Only a perfect, blemishless, sinless sacrifice could pay the price our sins deserve. Yet no man could ever live such a life. Hence the necessity of Christ being God, the Holy God - that He could actively obey in our place. The sacrifice must die to pay the wages that our sins have earned. God is eternal - He cannot die. Hence the necessity of Christ being man - that He could passively die in our place.
Hebrews says that the atoning work of this hypostatically united Christ did 'render powerless him who had the power of death, that is, the devil; and might deliver those who through fear of death were subject to slavery all their lives."
The divine Christ, in taking on flesh and blood, accomplished the purpose for which He was sent. "Satan draws men into sin that he might draw them into death"(Henry). Christ has rendered him powerless and He has delivered those who trust in Him from the slavish fear of death.
Are you scared of dying? Are you still in bondage to that slavish fear? If so, are you trusting in and meditating on the finished work of Christ. Through His mediatorial sacrifice and His victorious resurrection "death is now not only a conquered enemy but a reconciled friend." (Matthew Henry)
Is death a friend or a foe to you? Your answer may tell everything about your condition. "For to me, to live is Christ, and to die is gain." (Phil 1:21).