John Gill Commentary Psalms 145:3

"Great is Jehovah, and greatly to be praised; And his greatness is unsearchable." — Psalms 145:3 (ASV)

Great [is] the Lord, and greatly to be praised
Christ is the great God as well as our Saviour; great in all the perfections of his nature, of great wisdom, power, faithfulness, holiness, grace, and goodness; great in his person as God-man, God manifest in the flesh; great in all his offices and relations he bears and stands in to his people; and great in all his works of creation, providence, and redemption, in which he is concerned; and upon all which accounts he is to be praised, and greatly to be praised, by his people, even to the utmost of their capacities, here and hereafter; see (Psalms 48:1) ;

and his greatness [is] unsearchable ; the greatness of his nature, and the perfections of it, these are past finding out; and so are his ways and works, and the riches of his grace, (John 11:7) (5:9) (Ephesians 3:8) .

The Targum is, ``and of his greatness there is no end.'' So the Septuagint, Vulgate Latin, Syriac, and Arabic versions.