David
Psalm 40:5ESV·traditional attribution

You have multiplied, O LORD my God, your wondrous deeds and your thoughts toward us; none can compare with you! I will proclaim and tell of them, yet they are more than can be told.

John Calvin Reformed @genevareformer

PSALM 40 David, being delivered from some great danger, and it may be, not from one only, but from many, extols very highly the grace of God, and by means of this, his soul is filled with admiration of the providence of God, which extends itself to the whole human race.

Commenting on Psalm 40:1-17

C.H. Spurgeon Reformed Baptist @princeofpreachers

Many, O Lord my God, are thy wonderful works which thou hast done. Creation, providence, and redemption, teem with wonders as the sea with life. Our special attention is called by this passage to the marvels which cluster around the cross and flash from it.

Matthew Henry Presbyterian @wholebiblehenry

In these verses we have, I. The great distress and trouble that the psalmist had been in. He had been plunged into a horrible pit and into miry clay (Psa 40:2), out of which he could not work himself, and in which he found himself sinking yet further.

Commenting on Psalm 40:1-5