"day 15 of month 7." The word "month" refer to those in the Hebrew calendar. (See: [[rc://en/ta/man/jit/translate-hebrewmonths]] and [[rc://en/ta/man/jit/translate-ordinal]])
"gather together to worship and honor Yahweh." The phrase "a holy assembly" means the people gather together to worship Yahweh. Worshiping Yahweh is a holy event.