'Sabbath day' in the Bible

And it came to pass, that he was going on the sabbath day through the fields of grain: and his disciples began, as they went, to pull the ears of grain.

And the Pharisees said to him: See, why are they doing on the sabbath-day what is not lawful?

And they watched him, whether he would cure him on the sabbath-day, that they might accuse him.

And he said to them: Is it lawful to do good on the sabbath-day, or to do evil? to save life, or to kill? But they were silent.