This refers to everything associated with the preparation, the sacrifice, and the worship of Yahweh during the Passover. The word "service" can be expressed as a verb and this can be stated in active form. AT: "they did everything that needed to be done to serve Yahweh" (See: [[rc://en/ta/man/translate/figs-abstractnouns]] and [[rc://en/ta/man/translate/figs-activepassive]])
# kept the Passover
This is an idiom. AT: "observed the Passover" or "celebrated the Passover" (See: [[rc://en/ta/man/translate/figs-idiom]])
# then the Festival of Unleavened Bread
This refers to celebrating the festival. AT: "then kept the Festival of Unleavened Bread" or "then celebrated the Festival of Unleavened Bread" (See: [[rc://en/ta/man/translate/figs-ellipsis]])