Why did God become flesh and die on the cross?
God became flesh and died on the cross because He loved mankind; that is the only reason given. It was His unmerited favor, or grace, that the holy, sinless, sovereign Creator reached down to walk among men and suffer on a Roman cross for humanity.
Les teaches that grace is God's unmerited favor. The holy, sinless, righteous, creator, sovereign, powerful, infinite God reached down, became flesh, walked the filthy streets of Palestine and Jerusalem, heard the foul language of that day, and suffered and died on a Roman cross. Why? Because He loved mankind—that's the only reason. Les contrasts this with law: under law the key was commandment, but once grace comes in, the key is love, love, love. He also notes that most of Christendom does not comprehend or understand the grace of God.
Because the law worketh wrath: for where no law is, there is no transgression.
Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all,