What does "it" refer to here?

Context:

But supposing God became a man—suppose our human nature which can suffer and die was amal-
gamated with God's nature in one person—then that person could help us. He could surrender His
will, and suffer and die, because He was man; and He could do it perfectly because He was God. You
and I can go through this process only if God does it in us; but God can do it only if He becomes man.
Our attempts at this dying will succeed only if we men share in God's dying, just as our thinking can
succeed only because it is a drop out of the ocean of His intelligence: but we cannot share God's dying