The Bible says that God took on the likeness of a man when Jesus was born:
Philippians 2:5-7: Have this mind among yourselves, which is yours in Christ Jesus, who, though He was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, by taking the form of a servant, being born in the likeness of men. And being found in human form, He humbled himself by becoming obedient to the point of death, even death on a cross.
The Christmas song, “Away In A Manger” is usually thought of as a child’s song, but adults and children as well have enjoyed this song at Christmas time.
According to Country Music Notes the origin of the song is uncertain. I found both the origin and how it began in the USA to be uncertain. Country Music Notes tells us that:
No matter its start, the first two verses were first published in 1885 here in the United States. It was not until the early 1900’s that John T. McFarland wrote the third verse. He needed it for a children’s program to be performed at his Methodist church. Since then, children and adults alike have continued to love the precious tune that tells the story of Christ’s birth.
About.com has a different version:
The first publication of “Away in a Manger” was in 1885 in a Lutheran Sunday school book by James R. Murray. The author of the first two verses is unknown, but the third verse was composed by John T. McFarland. The music was composed by William J. Kirkpatrick in 1895.