Albert Barnes Commentary Psalms 66:8

"Oh bless our God, ye peoples, And make the voice of his praise to be heard;" — Psalms 66:8 (ASV)

O bless our God, you people — that is, particularly the people of the nation, the Hebrew people. The call here to praise or bless God is because of some special benefit that had been conferred on them, and which is referred to more specifically in the following verses. It was His gracious intervention in the time of danger, by which they were delivered from their enemies (Psalms 66:11–12).

And make the voice of His praise be heard — Let it be sounded out far, so that it may be heard widely.