If you like Petra, you might enjoy this band too -- same era, similar style.
Title: Independence Day
Artist: White Heart
Record Label: Star Song
It's on iTunes here. Don't be fooled by the preview -- it's rock, don't worry. The iTunes Store has a premonition for picking the cheesiest part of almost any song and setting that as the preview.
If you download the song (and you should), skip the first minute if you aren't American -- there's an Americana-type intro that I personally find boring and probably wouldn't interest anyone of any other nationality. (This is what you hear at the beginning of the iTunes Store preview, which is what makes the preview so misleading.)
Here it is on YouTube -- the intro previously mentioned isn't on this video.