'Observe' in the Bible

So some of the Pharisees were saying, "This man is not from God, because he does not observe the Sabbath!" Others were saying, "How can a man [who is] a sinner perform such signs?" And there was a division among them.

And if anyone hears my words and does not observe [them], I will not judge him. For I have not come to judge the world, but to save the world.