The Question: Why did Jesus descend/experience hell when he did nothing wrong?
Firstly, we must understand sin. Sin is our rebellion against God. It manifests itself in every one of our lives in so many different ways - pride, lust, envy, theft, etc. God must be just in this situation and therefore every sin must be dealt with. The punishment set for sin is death.
So, why does he care? Why doesn't he leave us in our sinful state?
This question drives at motivation.
The answer that the New Testament drives at over and over again is love. And it is a love for his creation that springs forth from Gen 1 & 2. We belong to God. He is grieved, angry in fact, over our rebellion and loves drives him to do something about it.
Rom 5:8
but God shows his love for us in that while we were still sinners, Christ died for us.
Eph 2:4-6
But God, being rich in mercy, because of the great love with which he loved us, 5 even when we were dead in our trespasses, made us alive together with Christ- by grace you have been saved- 6 and raised us up with him and seated us with him in the heavenly places in Christ Jesus,
1 Tim 1:14
and the grace of our Lord overflowed for me with the faith and love that are in Christ Jesus.
Titus 3:4
but when the goodness and loving kindness of God our Savior appeared,
1 Jn 3:16
By this we know love, that he laid down his life for us, and we ought to lay down our lives for the brothers.
And the list could go on.....
So, then Jesus experienced hell on the cross for us. That is the just anger of God needed to be satisfied and he himself provided the sacrifice. God was not angry with Jesus. God was pouring out his wrath and just judgment on our sin but the beauty, joy and sheer scandal of the gospel is that we were not there - Jesus was!! He provided his one and only Son. As we sing "In Christ Alone"
And on that cross as Jesus died
The wrath of God was satisfied
That Son, Jesus Christ, bore on the cross everything that was coming to me - his just anger which should result in death and exclusion from his kingdom.
BUT WHY? Why would he do something like that?
God was driven by his great love as we see in those earlier verses.
And again: Gal 2:20
I have been crucified with Christ and I no longer live, but Christ lives in me. The life I live in the body, I live by faith in the Song of God, who loved me and gave himself for me.
What person wouldn't want to believe this??