How would you answer the question: Why did Jesus become a man?
There are lots of angles to answer this question from, but here is one. Jesus became a man for me. He did so because there was no other way for me to be acceptable in God’s sight. God demands perfection, holiness, and spotless righteousness. The Son has always had these things. He didn’t need to prove it or earn it by becoming a man. Whereas I, on the other hand, could never have or attain these things on my own. But the Son having these things doesn’t mean he can merely give them to me or offer them to me, because he is God and I am human. If I am to have a perfect holy righteousness, it must be human. To receive such a thing from God, he must be human.
And so, God the Son became a man, Jesus Christ. As a man he live a perfect, righteous, and holy life, not for himself, but for me. Not to make himself acceptable to God, but that I might be acceptable before God.
Oh the wonder of the incarnation!