ANSWER: Since death is the punishment for sin, Christ died willingly in our place to deliver us from the power and penalty of sin and bring us back to God. By his substitutionary atoning death, he alone redeems us from hell and gains for us forgiveness of sin, righteousness, and everlasting life.
Can you name some events/passages in the Old Testament that foreshadow Christ's substitutionary atoning death?
In the commentary for this catechism question (see under "C" here) John Stott observes:
The concept of substitution may be said, then, to lie at the heart of both sin and salvation. For the essence of sin is man substituting himself for God, while the essence of salvation is God substituting himself for man. Man asserts himself against God and puts himself where only God deserves to be; God sacrifices himself for man and puts himself where only man deserves to be. Man claims prerogatives which belong to God alone; God accepts penalties which belong to man alone.
Do you think this is a good summary of our sin and God's salvation? Why or why not?
As you contemplate the atonement, you might appreciate these words from George Herbert on death and how Christ transformed it:
But since our Savior’s death did put some blood
Into thy face,
Thou art grown fair and full of grace,
Much in request, much sought for as a good.
For we do now behold thee gay and glad,
As at Doomsday;
When souls shall wear their new array,
And all thy bones with beauty shall be clad.
--From 'Death' by George Herbert