For me, although I love Christmas songs, this is a no brainer. It has to be "Oh Holy Night". It brings me to tears and all I can do is worship The Lord Jesus!
I love "O Holy Night" but I also love "what Child is This", and "O Come, O Come Emmanuel".
All three speak to me not just in their words, but also in the melody they create. "O Holy Night" leave you in awe of God, "What Child is This" creates a wonder of who God is, and "O Come, O Come Emmanuel" show the heart of man crying out for a savior.
I love to hear David Phelps sing "Oh Holy Night" it is a beautiful, meaningful song.
I think "God Rest Ye Merry Gentlemen" ministers to me a lot throughout the year with it's comforting words of truth. We never hear all of the verses to most of these songs and I love to read them as they were deeply inspired.
I am not really into Christmas music...and have not bought a Xmas CD in years until last week, I bought "A Christmas Cornucopia" by Annie Lennox...it has a nice version of "God Rest Ye Merry Gentlemen" .
