'Lawful' in the Bible

The Pharisees asked him, "Look! Why are they doing what is not lawful on Sabbath days?"

How was it that he went into the House of God during the lifetime of Abiathar the high priest and ate the Bread of the Presence, which was not lawful for anyone but the priests to eat, and gave some of it to his companions?"

Then he asked them, "Is it lawful to do good or to do evil on Sabbath days, to save a life or to destroy it?" But they remained silent.

John had been telling Herod, "It's not lawful for you to have your brother's wife."

Some Pharisees came to test him. They asked, "Is it lawful for a man to divorce his wife?"

They came and told him, "Teacher, we know that you are sincere. You don't favor any individual, because you pay no attention to external appearance. Rather, you teach the way of God truthfully. Is it lawful to pay taxes to Caesar or not? Should we pay them or shouldn't we?"