'Observe' in the Bible

The Lord said to me, "I have made you like a metal assayer to test my people like ore. You are to observe them and evaluate how they behave."

Do not carry any loads out of your houses or do any work on the Sabbath day. But observe the Sabbath day as a day set apart to the Lord, as I commanded your ancestors.

All the people living in Jerusalem and all the people who came into Jerusalem from the towns of Judah came to observe a fast before the Lord. The fast took place in the ninth month of the fifth year that Jehoiakim son of Josiah was ruling over Judah.