Oh give thanks unto the God of gods; For his lovingkindness [endureth] for ever. (ASV)
"God of gods". Note the reference to a plurality of gods: the Hebrews originally believed in the existence of many gods. For more on this topic, see the Deuteronomy 32:8 section.
"God of gods". This sort of formulation, [noun] of [plural same noun], is common in ancient Hebrew as a means of expressing the greatness of a person or thing. As a figure of speech, this example doesn't necessarily give evidence of polytheism whereas other verses do more clearly.
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