'Lawful' in the Bible

Then Jesus said to them, “I ask you directly: Is it lawful to do good on the Sabbath or to do evil, to save a life or to destroy it?”

And Jesus asked the lawyers and the Pharisees, “Is it lawful to heal on the Sabbath, or not?”

Is it lawful [according to Jewish law and tradition] for us to pay taxes (tribute money) to Caesar or not?”