'Serve the Lord' in the Bible

"Instruct the Israelis that when any of you or your descendants becomes unclean due to contact with a corpse, or if he is on a long journey, he nevertheless is to observe the LORD's Passover.

If a resident alien lives with you and wants to observe the LORD's Passover, let him observe it according to the statutes and laws of the Passover. You are to maintain the same statute for the resident alien as you do for the native of the land."