Here the word "keep" means to observe. AT: "observe the Festival of the Passover" or "celebrate the Festival of the Passover" (See: [[rc://en/ta/man/translate/figs-idiom]])
# in the first month, on the fourteenth day of the month
"on day 14 of the the first month." This refers to time in the Jewish calendar. (See: [[rc://en/ta/man/translate/translate-hebrewmonths]] and [[rc://en/ta/man/translate/translate-ordinal]])