Antagonistic critics of the Bible poke fun at crude laws in the Old Testament. For example, Deuteronomy 22:28–29 says that if a man seizes an unengaged virgin and forces sexual intercourse (rape), then that man must pay dowry to the virgin's father and permanently marry the virgin. In this case, Mosaic Law says that the rape should result in marriage.
Fortunately, Jesus Christ and the apostolic church taught about limits for Mosaic Law. For example, Mark 7:1–23:
 Now when the Pharisees and some of the scribes who had come from Jerusalem gathered around him [Jesus],  they noticed that some of his disciples were eating with defiled hands, that is, without washing them.  (For the Pharisees, and all the Jews, do not eat unless they thoroughly wash their hands, thus observing the tradition of the elders;  and they do not eat anything from the market unless they wash it; and there are also many other traditions that they observe, the washing of cups, pots, and bronze kettles.)  So the Pharisees and the scribes asked him, "Why do your disciples not live according to the tradition of the elders, but eat with defiled hands?"  He said to them, "Isaiah prophesied rightly about you hypocrites, as it is written,Christ taught about Mosaic Law in response to Jewish leaders called Pharisees and scribes who criticized Christ's disciples. The Jewish leaders criticized the disciples for impurity (defilement) because they neglected to ceremoniously wash their hands before eating. This hand washing was not a mere issue of healthy living, but Jewish tradition developed a hand washing ceremony and other ceremonial washings untaught in Mosaic Law. In this case, there were no biblical grounds for criticizing the disciples while they disregarded an extra-biblical ceremony. Christ responded by accusing the Jewish leaders of directly disobeying the prophet Isaiah and Mosaic Law. Christ quoted Isaiah's rebuke of Israelites who honored God only with their words but not their hearts. And Christ said that the Jewish leaders abandoned God's commandments for mere human tradition. Christ then described how many Jews broke the biblical commandment of honoring their parents. In these cases, the elderly parents of various Jews needed financial support, but their progeny instead devoted money to God that could have helped their needy parents. These Jews may have looked good in public for giving financial offerings to God, but they neglected to honor their parents by helping them in their need. Christ concluded this public speech by proclaiming that no oral consumption makes a person impure, which superseded Mosaic dietary laws. Christ later explained to his disciples that sins such as fornication, adultery, and licentiousness begin in the heart of humans.
'This people honors me with their lips,
but their hearts are far from me;
 in vain do they worship me,
teaching human precepts as doctrines.'
 You abandon the commandment of God and hold to human tradition."
 Then he said to them, "You have a fine way of rejecting the commandment of God in order to keep your tradition!  For Moses said, 'Honor your father and your mother'; and, 'Whoever speaks evil of father or mother must surely die.'  But you say that if anyone tells father or mother, 'Whatever support you might have had from me is Corban' (that is, an offering to God) —  then you no longer permit doing anything for a father or mother,  thus making void the word of God through your tradition that you have handed on. And you do many things like this."
 Then he called the crowd again and said to them, "Listen to me, all of you, and understand:  there is nothing outside a person that by going in can defile, but the things that come out are what defile."
 When he had left the crowd and entered the house, his disciples asked him about the parable.  He said to them, "Then do you also fail to understand? Do you not see that whatever goes into a person from outside cannot defile,  since it enters, not the heart but the stomach, and goes out into the sewer? (Thus he declared all foods clean.)  And he said, "It is what comes out of a person that defiles.  For it is from within, from the human heart, that evil intentions come: fornication, theft, murder,  adultery, avarice, wickedness, deceit, licentiousness, envy, slander, pride, folly.  All these evil things come from within, and they defile a person." (Mark 7:1–23)
Christ also in Mark 14:49 and Matthew 5:17 referred to himself as the fulfillment of the scriptures that included Mosaic Law, and Hebrews 9:1—10:19 says that Christ fulfilled all ceremonial Mosaic Law. Additionally, John 8:2–11 portrays Christ in a scenario where he disregards Mosaic Law that says he should have stoned an adulterous. (Despite the controversy that this passage is an interpolation, the interpolation represents belief and practice in the early church.)
All of this from the Gospels and Hebrews indicates that New Covenant principles supersede Mosaic Law. However, Christ affirmed the immutability of some Mosaic Law when he taught that adultery is evil. Likewise, Christian's may disregard a literal application of dietary Mosaic Law and punishments prescribed in Mosaic Law, but Christian's should never disregard immutable Mosaic Law such as the prohibition against adultery.
This article focuses on the role of Mosaic Law in Christian life while this series focuses on sacred sex and celibacy. But since I began this article with a reference to Deuteronomy 22:28–29 that is repugnant to many people in modern times, then I want to briefly explain how such a law ever made it into the Bible. As stated earlier, the passage says that if a man seizes an unengaged virgin and forces sexual intercourse, then that man must pay dowry to the virgin's father and permanently marry the virgin. In the ancient context, the law protected the woman from a life of scorn and impoverished spinsterhood. Also, given that the rapist of a married or engaged woman faced the death penalty and the average man then could not afford polygamy, then the law made no opportunity for serial rapists and forced the man to turn into a responsible provider for the woman.
Finally, a common criticism against Christian moralizers who quote the Old Testament is that they arbitrarily pick and choose the biblical verses that they promote. I agree that many Christian moralizers appear to arbitrarily pick and choose biblical verses. However, as indicated in this article, a biblical basis teaches discretion when picking and choosing biblical verses that teach biblical ideals. In the case of morals and ethics, I promote a discretionary rule indicated in the Bible: New Testament principles filter Mosaic Law. In other words, Christians should disregard the literal application of Mosaic Law unless the New Testament teaches that a particular law is an ideal. For example, Christ taught the disregard of dietary Mosaic Law while supporting the prohibition against adultery.
Copyright © 2012 James Edward Goetz
New Revised Standard Version Bible, copyright 1989, Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.