'Observe' in the Bible

All therefore whatsoever they bid you observe, that observe and do; but do not ye after their works: for they say, and do not.

Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen.

And teach customs, which are not lawful for us to receive, neither to observe, being Romans.

As touching the Gentiles which believe, we have written and concluded that they observe no such thing, save only that they keep themselves from things offered to idols, and from blood, and from strangled, and from fornication.

Ye observe days, and months, and times, and years.

I charge thee before God, and the Lord Jesus Christ, and the elect angels, that thou observe these things without preferring one before another, doing nothing by partiality.