Albert Barnes Commentary Psalms 75:9

"But I will declare for ever, I will sing praises to the God of Jacob." — Psalms 75:9 (ASV)

But I will declare for ever - I - the author of the psalm. I will make known at all times the character of God, and will declare the truth respecting his works and ways. The particular mode as referred to here was praise.

I will sing praises to the God of Jacob - The God whom Jacob worshipped; the God who proved himself to be his Friend, thus showing that he is the Friend of all that trust in him. See the notes at (Psalms 24:6).