Possible meanings are that the rulers of the nations 1) "gather in front of the people" or 2) "gathered together with the people" so that all may worship God as king.
Possible meanings are that "shields" 1) refers to instruments of war. AT: "God has more power than the weapons of all the kings on the earth" or 2) refers to the rulers of the nations who are spoken of as shields who protect their nations. AT: "the kings of the earth are subject to God" (See: [[rc://en/ta/man/translate/figs-metaphor]])