David
Psalm 66:9BSB·traditional attribution

He preserves our lives and keeps our feet from slipping.

John Calvin Reformed @genevareformer

PSALM 66 There may have been one deliverance in particular, which the Psalmist celebrates here in the name of the Church, but he includes the many and various mercies which God had all along conferred upon his chosen people. While he takes notice of the divine interposition in their behalf, in a crisis of great mercy and distress, he suggests it as matter of comfort...

Commenting on Psalm 66:1-20

C.H. Spurgeon Reformed Baptist @princeofpreachers

Which holdeth our soul in life. At any time the preservation of life, and especially the soul's life, is a great reason for gratitude but much more when we are called to undergo extreme trials, which of themselves would crush our being. Blessed be God, who, having put our souls into possession of life, has been pleased to preserve that heaven given life from the destroying power of the enemy.

Matthew Henry Presbyterian @wholebiblehenry

In these verses the psalmist calls upon God's people in a special manner to praise him. Let all lands do it, but Israel's land particularly. Bless our God; bless him as ours, a God in covenant with us, and that takes care of us as his own.

Commenting on Psalm 66:8-12