I was very surprised, when I first heard this song, how much I loved it. I was surprised not because it was Amy Grant - the woman can sing, and I already knew that - and not because it was so openly religious - this wasn't the first Amy Grant song I ever heard - but because it was lifted almost straight out of Psalm 119:105. I didn't expect a song with lyrics so ancient could sound so lovely, and yet she and Michael W. Smith took those words and made them into a beautiful song.
Of course, they added lyrics - it's said that the added lyrics came to Amy when she was lost in the Colorado mountain darkness - but the base of this song was still biblical.
"Thy Word" is from Amy's 1984 album Straight Ahead, her last as a pure Myrrh Records artist. Christian record labels have such distinctive names. It would be the first ever Myrrh Records album - first Christian pop/rock album, in fact - to ever hit the Billboard Top 200 album chart. I did not discover this song then, but several years later, on The Collection, which was her first "greatest hits" album and a monstrous commercial success. This was my favorite song on the entire compilation, and remains to this day my favorite Amy Grant song.
The version below is from a live performance in 2004, with the two songwriters collaborating. Amy tells a nice story before they start playing.