Albert Barnes Commentary Psalms 106:48

"Blessed be Jehovah, the God of Israel, From everlasting even to everlasting. And let all the people say, Amen. Praise ye Jehovah. BOOK V" — Psalms 106:48 (ASV)

Blessed be the Lord God of Israel from everlasting to everlasting — Forever. As he has been adored in the past—even from the beginning of the creation—so let him be adored and praised in all periods to come—forever and ever. See the notes at Psalms 41:13.

And let all the people say, Amen — In Psalms 41:13, this is, Amen and amen. The idea is, let all the people join in this; let them all express and declare their assent to this: let them all say, “Be it so.” The word “Amen” is a word expressing assent—meaning truly, certainly.

Praise ye the Lord — Hebrew, “Hallelujah.” See Psalms 104:35.