ANSWER: That in human nature he might on our behalf perfectly obey the whole law and suffer the punishment for human sin; and also that he might sympathize with our weaknesses.
This catechism question seems to beg us to look at the letter to the Hebrews...
Take a look at Hebrews 2:14-18. Why do you think the author emphasizes that Jesus didn't help the angels but rather the children of Abraham? What vocation that we usually think of as an "Old Testament role" does Jesus have, according to the author? What did the people in this role traditionally do?
Now, turn to Hebrews 5. When Jesus acts as our high priest, how is he similar to the high priests who came before him? How is he different?
As you think about the truly human Redeemer, may these words from Hebrews 10 serve as an encouragement to you:
So, friends, we can now—without hesitation—walk right up to God, into “the Holy Place.” Jesus has cleared the way by the blood of his sacrifice, acting as our priest before God. The “curtain” into God’s presence is his body.
So let’s do it—full of belief, confident that we’re presentable inside and out. Let’s keep a firm grip on the promises that keep us going. He always keeps his word. Let’s see how inventive we can be in encouraging love and helping out, not avoiding worshiping together as some do but spurring each other on, especially as we see the big Day approaching.--Hebrews 10:19-25 in The Message