From St. Gregory of Nyssa:"Do you ask why God was born among men? Here is the reason for God's presence among men. Our nature was sick and needed a doctor. Man had fallen and needed someone to raise him up. He who had ceased to participate in the good needed someone to bring him back to it. He who was shut in darkness needed the presence of life. The prisoner was looking for someone to ransom him, the captive for someone to take his part. He who was under the yoke of slavery was looking for someone to set him free. Were these small and unworthy reasons to make God to come down and visit human nature?"
From a commentary on the Nicene Creed.