'Observe' in the Bible

All things therefore whatever they tell you to observe, observe and do, but don't do their works; for they say, and don't do.

teaching them to observe all things that I commanded you. Behold, I am with you always, even to the end of the age." Amen.

and set forth customs which it is not lawful for us to accept or to observe, being Romans."

But concerning the Gentiles who believe, we have written our decision that they should observe no such thing, except that they should keep themselves from food offered to idols, from blood, from strangled things, and from sexual immorality."

He who observes the day, observes it to the Lord; and he who does not observe the day, to the Lord he does not observe it. He who eats, eats to the Lord, for he gives God thanks. He who doesn't eat, to the Lord he doesn't eat, and gives God thanks.

You observe days, months, seasons, and years.

I command you in the sight of God, and Christ Jesus, and the chosen angels, that you observe these things without prejudice, doing nothing by partiality.