Psalms 106:48

Blessed be the Lord God of Israel
God is to be blessed as the Father of mercies; as the God and Father of our Lord Jesus Christ; and as the covenant God and Father of his people in him, of the true Israel of God: which is done by celebrating his blessedness in himself; by ascribing to him all blessedness enjoyed, as the author of it; and by giving him honour, glory, and blessing for it.

From everlasting to everlasting;
here and hereafter, in time and to all eternity; from this world to that which is to come, as the Targum; and which Arama observes are the days of the Messiah.

And let all the people say, Amen;
so be it; to giving thanks to God, to praising his name, and ascribing blessing to him.

Praise ye the Lord;
or "hallelujah"; so these two words, "Amen, hallelujah", are joined together in ( Revelation 19:4 ) . The psalm ends as it began; for though the greatest part of it is taken up in relating the sins of the people of Israel; yet as the Lord was merciful to them and forgave them, and notwithstanding bestowed great mercies on them, there was reason for praise and thanksgiving. Here ends the fourth part of the book of Psalms; the fifth part begins, with the following psalm.