This is an idiom. AT: "determined himself to seek" or "devoted himself to seek" (See: [[rc://en/ta/man/translate/figs-idiom]])
# to seek Yahweh
This speaks of seeking Yahweh's advice as if he were looking for Yahweh. AT: "to seek Yahweh's advice" (See: [[rc://en/ta/man/translate/figs-metonymy]])
# He proclaimed a fast
The word "fast" can be expressed as a verb. AT: "He proclaimed that all the people should fast" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])