In Psalm 40:2, after lifting him out of the miry clay, God set the psalmist's feet upon what?

Answer: A rock

Psalm 40:2: "He lifted me up from the pit of despair, out of the miry clay; He set my feet upon a rock, and made my footsteps firm."

“He lifted me up from the pit of despair, out of the miry clay; He set my feet upon a rock, and made my footsteps firm.”— Psalm 40:2 (BSB)