Absolute rules of behavior are applicable for all societies, all religions, all cultures, all geographical areas and all eras. "Thou shalt not murder" from the Ten Commandments is a good example.

Relative rules of behavior are not universal but are applicable only for one society, or one area of the world, or one time period in history. One example is the prohibition against eating pork or shellfish. With the advent of refrigeration and improved cooking methods, pork and shellfish can now be consumed safely . What was necessary in ancient times to avoid food poisoning is no longer applicable.

Consider the topic of pre-marital sex:

	Some would argue that Paul's prohibition of pre-marital sex is absolute -- covering all individuals, all societies and all eras.
	Others argue that the need for virginity before marriage was critical in the 1st century CE, when: There was no effective contraceptive methods to prevent pregnancy. Then as now, a child being brought up in a single parent home tends to be disadvantaged. A woman with a child could not survive without the support of a father or husband. There was no dependable method of avoiding transferring sexually transmitted diseases (STDs) There were no effective treatments or cures for STD. The average time interval between puberty and marriage was only a few years -- perhaps even months.
	But with the availability of good birth control methods, financial support programs, safe-sex practices, effective treatments for most STDs, they might argue that sex between a committed, monogamous couple who practice safer sex is not a sin. They might conclude that since the time interval between puberty and marriage is now on the order of 15 years, it is impractical to  expect most youth to maintain a state of virginity until marriage