'Adultery' in the Bible

Ye have heard that it has been said, Thou shalt not commit adultery.

But I say unto you, that every one who looks upon a woman to lust after her has already committed adultery with her in his heart.

But I say unto you, that whosoever shall put away his wife, except for cause of fornication, makes her commit adultery, and whosoever marries one that is put away commits adultery.

But I say unto you, that whosoever shall put away his wife, not for fornication, and shall marry another, commits adultery; and he who marries one put away commits adultery.

He says to him, Which? And Jesus said, Thou shalt not kill, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness,