This is a piece of music that when sung, particularly by men's choir, moves me to tears. I remember it from JFK's funeral.
Part of what makes it beautiful is the walk-up (ascending parallel third run) in the tenor and bass in the first line and the modulation on 'ocean deep' that makes a dissonance all through that line, and resolves finally on 'hear us when we cry to Thee'.
The song is in a number of mainstream Protestant hymnbooks. I have it here in "The Worship Book", from Westminster Press in Philadelphia. In my experience one can usually purchase hymnbooks from a church or used bookstore.
Hope this helps
Blessings,
Barbara