From YOUCAT, fact 76:
76: Why did God become man in Jesus?
“For us men and for our salvation he came down from heaven” (Nicene –> Creed). [456-460]
In Jesus Christ, God reconciled the world to himself and redeemed mankind from the imprisonment of sin. “God so loved the world that he gave his only-begotten Son” (Jn 3:16). In Jesus, God took on our mortal human flesh (–> INCARNATION), shared our earthly lot, our sufferings, and our death, and became one like us in all things but sin.