'Observe' in the Bible

""You are to observe the Festival of Unleavened Bread, since on this very day I brought your tribal divisions from the land of Egypt. You are to observe this day from generation to generation as a perpetual ordinance.

You are to observe this event as a perpetual ordinance for you and your children forever.

When you enter the land that the LORD will give you, just as he promised, you are to observe this ritual.

The whole congregation of Israel is to observe it.

If an alien who resides with you wants to observe the Passover to the LORD, every male in his household must be circumcised, and then he may come near to observe it. He is to be like a native of the land, but no uncircumcised person is to eat it.

When the LORD brings you to the land of the Canaanite, the Hittite, the Amorite, the Hivite, and the Jebusite, which he swore to your ancestors to give you a land flowing with milk and honey you are to observe this ritual in this month.

You are to observe the Festival of Unleavened Bread. As I commanded you, you are to eat unleavened bread for seven days at the appointed time in the month Abib, because in it you came out of Egypt. No one is to appear before me empty handed.

You are to observe the Festival of Harvest, celebrating the first fruits of your work in planting the field, and the Festival of Tabernacles at the end of the year, when you gather the fruit of your work from the field.

"You are to tell the Israelis: "You are to certainly observe my Sabbaths because it's a sign between me and you from generation to generation, so you may know that I am the LORD who sanctifies you.

You are to observe the Sabbath, because it's holy for you. Whoever profanes it is certainly to die; indeed, whoever does work on it is to be cut off from among his people.

"You are to observe the Festival of Unleavened Bread. For seven days, at the appointed time in the month Abib, you are to eat unleavened bread as I commanded you, for in the month Abib you came out of Egypt.

"You are to observe the Festival of Weeks, the first fruits of the wheat harvest, and the Festival of Tabernacles at the turn of the year.