I will sing of the mercies of the Lord for ever: with my mouth will I make known Thy faithfulness to all generations.@Psalm 89:1
Isaac Watts (1674–1748)

Isaac Watts, The Psalms of David 1719. The faithfulness of God.

Caithness Scottish Psalter, 1635 (🔊 pdf nwc).

My never ceasing songs shall show
The mercies of the Lord,
And make succeeding ages know
How faithful is His Word.

The sacred truths His lips pronounce
Shall firm as Heav’n endure;
And if He speak a promise once,
Th’eternal grace is sure.

How long the race of David held
The promised Jewish throne!
But there’s a nobler covenant sealed
To David’s greater Son.

His seed for ever shall possess
A throne above the skies;
The meanest subject of His grace
Shall to that glory rise.

Lord God of hosts, Thy wondrous ways
Are sung by saints above;
And saints on earth their honors raise
To Thy unchanging love.