Albert Barnes Commentary Psalms 9:1

"I will give thanks unto Jehovah with my whole heart; I will show forth all thy marvellous works." — Psalms 9:1 (ASV)

I will praise thee, O Lord - That is, in view of the merciful interpositions referred to in the psalm (Psalms 9:3–5), and in view of the attributes of God’s character which had been displayed on that occasion (Psalms 9:7–12).

With my whole heart - Not with divided affection, or with partial gratitude. He meant that all his powers should be employed in this service; that he would give utterance to his feelings of gratitude and adoration in the loftiest and purest manner possible.

I will show forth - I will recount or narrate - namely, in this song of praise.

All thy marvelous works - All his works or doings fitted to excite admiration or wonder. The reference here is particularly to what God had done that gave occasion to this psalm. Still, the psalmist undoubtedly intends to connect with this the purpose of giving a general expression of praise in view of all that God had done that was fitted to excite such feelings.