Albert Barnes Commentary Psalms 146:5

"Happy is he that hath the God of Jacob for his help, Whose hope is in Jehovah his God:" — Psalms 146:5 (ASV)

Happy is he that hath the God of Jacob for his help - Who may rely for protection on the God who defended Jacob in his travels and dangers. Or, perhaps the word Jacob is used here collectively to denote Israel—the Jewish people: the God whom they adore and worship, rather than the gods of the pagan. Compare Psalms 144:15, note; Psalms 54:4, note.

Whose hope is in the Lord his God - In Yahweh, worshipped as his God. That is, who truly worships Yahweh, or makes Yahweh his God.