As of late I have not been able to stop listening to Sandra McCracken's version of this song.
The lyrics, which I believe is from a Puritan hymn, are incredibly moving.
Thy mercy my God is the theme of my song,
The joy of my heart, and the boast of my tongue.
Thy free grace alone, from the first to the last,
Hath won my affection and bound my soul fast.
Without Thy sweet mercy, I could not live here.
Sin would reduce me to utter despair,
But through Thy free goodness, my spirit's revived
And He that first made me still keeps me alive.
Thy mercy is more than a match for my heart,
Which wonders to feel its own hardness depart.
Dissolved by Thy goodness, I fall to the ground
And weep for the praise of the mercy I've found.
Great Father of mercies, Thy goodness I own
In the covenant love of Thy crucified Son.
All praise to the Spirit, Whose whisper divine
Seals mercy and pardon and righteousness mine.