1 AS debtors to mercy alone,
Of heavenly mercy we sing;
Nor fear to draw near to the throne,
Our praise and our worship to bring:
The wrath of a sin-hating God
With us can have nothing to do;
The Saviour's obedience and blood
Hide all our transgressions from view.
2 The work which His goodness began,
The arm of His strength will complete:
His promise is Yea and Amen,
And never was forfeited yet:
Things future, nor things that are now,
Nor all things below nor above,
Can make Him His purpose forgo,
Or sever our souls from His love.
3 Our names from the palms of His hands
Eternity will not erase:
Impressed on His heart they remain
In marks of indelible grace:
And we to the end shall endure,
As sure as the earnest is given;
More happy, but not more secure,
The spirits departed to heaven.
The hymn was in all the hymn books from Wigram's 1838 Poor of the Flock. It didn't make it into the 1932 edition, though, so isn't in any subsequent Little Flock.
I haven't checked what changes were made in the various editions in which it did appear but I shall do and report back.