Religious traditions are ways of thinking and acting which are thought to be in conformity with God's will. The fundamental Law of God said to love God and neighbor and Christ supported this law but Jewish practices that grew up around the fundamental law moved away from the spirit of the law.
The third commandment said, Remember the Sabbath day by keeping it holy. Six days you shall labor and do all your work, but the seventh day is a Sabbath to the Lord your God. " (Ex 20:8) The Jewish teachers of the law took it upon themselves to spell out what this meant in great detail. For example, one Saturday "Jesus was going through a field of grain on the Sabbath. His disciples were hungry and began to pick the heads of grain and eat them." (Mt 12:1) This action disobeyed Keeping of the Sabbath. They tested Jesus to see if he would heal on the Sabbath. Christ pointed out to the Jews that the Sabbath was made for man and not man for the Sabbath. It was supposed to be a day of rest so that man could use the time to worship and refresh his spirit. Healing the sick was thought to be unlawful work on the Sabbath but Jesus saw their hypocrisy. If an animal fell into a pit on the Sabbath, they would pull it out but they were against relieving the burden of a sick woman. By their traditions, they disregard the law of love of neighbor. The many detailed prohibiting work on the Sabbath had become a burden, they violated the purpose or spirit of the law.
On one occasion the Pharisees noted that the apostle did not wash their hands before eating. Christ said, Oh you Pharisees! Although you cleanse the outside of the cup and the dish, inside you are filled with plunder and evil." (Lk 11:39) And regarding clean and unclean food Christ noted, "Do you not realize that everything that goes into a person from outside cannot defile, since it enters not the heart but the stomach and passes out into the latrine? (Thus he declared all foods clean.) But what comes out of a person, that is what defiles. From within people, from their hearts, come evil thoughts, unchastity, theft, murder, adultery, greed, malice, deceit, licentiousness, envy, blasphemy, arrogance, folly. All these evils come from within and they defile. (Mk 7:18-23) Christ further explains, "You have heard that it was said,You shall not commit adultery. But I say to you, everyone who looks at a woman with lust has already committed adultery with her in his heart." (Mt 5:27-28) On the other hand, Christ was not against tradition as such. One day a man with leprosy asked Jesus to heal him. Jesus touched and healed the man and told him to show himself to the priest and offer the gift Moses commanded.(Mt. 8:1-4)
Did Jesus become unclean by touching the leper? Technically, yes, but as the Son of God he knew that the laws of purity were temporary because they were meant to pave the way for to purity of soul. "He [Jesus] cleansed. He showed us that He is the one who takes away the corruption of the curse of creation, which was the result of the Fall of Man." (blogspot.com/100 Answers in 100 days: The Purpose of the Old Testament Purity Laws by Emeth) St. Paul tells us that no one is justified by the works of the Law, the law of Moses which included the laws of purity. It is faith in Jesus Christ which saves us. This does not mean that we are justified by faith alone. "Justification is received by faith and perfected by law of charity but it is not earned by works alone."