Before we answer the question that if Jesus is God, how can he, as God, die, we need to explain Christian theology. When we say that Jesus is God, we are saying that Jesus is both human and divine; that is, he is both God and man. This is called the hypostatic union. It is the teaching that within the one person of Christ are two distinct natures: divine and human. We see evidence of this in such verses as the following:
- John 1:1,14, "In the beginning was the Word, and the Word was with God, and the Word was God... 14 And the Word became flesh, and dwelt among us..."
- John 20:28, "Thomas answered and said to Him, 'My Lord and my God!'”
- Col. 2:9, "For in Him all the fulness of Deity dwells in bodily form."
So when we say that Jesus is God, we are saying that within the one person who is Christ is the human nature and the divine nature. Therefore, we see that Jesus is God because he has both the nature of man and of God. But when Jesus died on the cross, it was not his divine nature as God that died. It was the human nature that died. Dying is a biological function that was reserved only for the human nature of Christ when he died on the cross.
We perceive the divine through the human
Also, we have to understand that we perceive the divine nature through human nature. It is not as though we can see what color divinity is or how much it weighs. If it is like human nature, what is it? How do we discover it? Is it blue? Does it glow? How much does it weigh? The truth is that we can't see what human nature is any more than we can see what the divine nature is. However, we can see the attributes of humanity in biological structures. For example, we have two arms, two legs, a head, etc. But we also see other attributes of humanity such as decision-making, morality, the ability to love, worship, etc., and other attributes that are implicit with human nature. So we see the human nature in the expression of its attributes, both physical and "internal."
Likewise, we can see the divine nature of Christ through his human nature. We see how the person of Jesus exercised divine attributes when he walked on water (Matt. 14:29), forgave sins (Luke 5:20), claimed to preexist with the Father (John 17:5), said that he would be with the disciples always (Matthew 28:20), etc.
So, Jesus is both divine and human; that is, he is both God and man. When we say that Jesus is God and that Jesus died on the cross, we are not saying that the God-nature died. Rather, we are saying the person of Christ died and that the person of Christ had divine attributes.