Matt. 5:28 But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart. 

Exo. 20:14 Thou shalt not commit adultery.  

1 Cor. 6:18  Flee fornication. Every sin that a man doeth is without the body; but he that committeth fornication sinneth against his own body.

Gal. 5:17 For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.

Rom. 1:18-32 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; Because that which may be known of God is manifest in them, for God shewed it unto them. For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so they are without excuse: Wherefore God also gave them up to uncleanness through the lusts of their own hearts, to dishonour their own bodies between themselves; Who changed the truth of God into a lie, and worshipped and serve the creature more than the Creator, who is blessed for ever, Amen. For this cause God gave them up unto vile affections: for even their women did change natural use into that which is against nature: And likewise also the men, leaving yhe natural use of the woman, burned in their lust one toward another; men with men working that which is unseemly, and receiving in themselves that recompence of their error which was meet. And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient; Being filled with all unrighteous, fornication, wickedness, covetousness, maliciousness; full of envy, murder, debate, deceit, malignity; whisperers; Backbiters, haters of God, despiteful, proud, boasters, inventors of evil things, disobedient to parents, Without understanding, covenant breakers, without natural affection, implacable, unmerciful: Who knowing the judgment of God, that they which commit such things are worthy of death. not only do the same, but have pleasure in them that do them.