'Sabbath day' in the Bible

They went into Capernaum, and immediately on the Sabbath day he entered into the synagogue and taught.

It happened that he was going on the Sabbath day through the grain fields, and his disciples began, as they went, to pluck the ears of grain.

The Pharisees said to him, "Behold, why do they do that which is not lawful on the Sabbath day?"

They watched him, whether he would heal him on the Sabbath day, that they might accuse him.

He said to them, "Is it lawful on the Sabbath day to do good, or to do harm? To save a life, or to kill?" But they were silent.