Reference for Psalms 136:2

ה֭וֹדוּ לֵֽאלֹהֵ֣י הָאֱלֹהִ֑ים כִּ֖י לְעוֹלָ֣ם חַסְדּֽוֹ׃

O give thanks unto the God of gods, For His mercy endureth for ever.

BDB