Complete Psalm 103:1: "Bless the LORD, O my ___; all that is within me, bless His holy name."

Answer: soul

Psalm 103, a psalm of David, opens: "Bless the LORD, O my soul; all that is within me, bless His holy name."

“Of David. Bless the LORD, O my soul; all that is within me, bless His holy name.”— Psalm 103:1 (BSB)