'Is It Lawful' in the Bible

And he saith to them, Is it lawful on the sabbath day to do good, or to do evil, to preserve life, or to kill? but they were silent.

And the Pharisees coming to him, put a question to him, Is it lawful for a husband to put away his wife? tempting him.

And they come and say to him, Master, we know that thou art true, and carest not for any man: for thou regardest not the person of men, but teachest the way of God in truth: Is it lawful to pay tribute to Caesar, or not?