What does the Bible say about pornography?
Pornography has been around for centuries. Using the strict definition of it as "writing about prostitution," even as early as the Romans we find pornographic literature. Yet the Bible does not directly address the issue. Maybe that is because God considers it a symptom rather than a root disease.
The root is not the writings or pictures. The root is our attitude toward marriage. Basically, God has determined that marriage is the appropriate venue for our sexual expression. "Marriage is honourable in all, and the bed undefiled: but whoremongers and adulterers God will judge." (Heb 13:4) One who seeks to defile the marriage, or to violate one's promises to the spouse, or to have "one without the other" (the song, "Love and Marriage" just happens to be playing on the radio as I write this), is opposing God. Pornography as a whole advocates any or all of these things, and that is what makes it wrong. "Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things." (Philippians 4:8)
Some would quote Matthew 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." Others say that the word "lust" is more than just looking, but includes a desire so strong that one acts upon that desire. By that definition, just looking at or reading pornography would not be included, unless it led to an action. By that reading Jesus is saying that if one lusts after a woman and commits adultery with her, it is because the adultery started in the heart. So it is not clear that this passage applies to pornography. Nevertheless, the idea of pornography as promoting unscriptural practices still may apply.