Jesus was merely challenging the elevation of man made traditions into sacred standings when he contested the Coban law (Mt 15:1-9). He was against the fact that people: Pharisees, Sadducees and scribes were neglecting their responsibilities to their parents in order to fulfill this law. If you made a Corban vow, you were to fulfill it. Some kept it but neglected their responsibilities to their parents. To Jesus, neglecting the other commandment that said honor your parents merited death just as failure to fulfill the Corban vow merited death. The Corban vow was a tradition that was elevated to a sacred standing. How many people give money to churches, ministries and charities but their parents, relatives or children are struggling with rents? Consequently, you were breaking the same law you were trying to keep in the vow. That does not mean Jesus was encouraging people to kill their children.
What Jesus meant in Mt 5:20 that your righteousness must exceed that of the scribes and Pharisees was that, your righteousness should not be artificial, synthetic or perfunctory. It should be from the heart. They did it to win human praises, but they should do it for real and if for real then they will not go and give to the temple in other to fulfill the Corban Vow while neglecting their parents who needed help. How many people give money in church just so people notice them while their families are in desperate need of lesser help? Such was the righteousness of the Pharisee, and to Jesus it was tantamount to hypocrisy.
In mt 5: 17, you will have to find out which laws. When we talk of the laws and the prophets, we mean the moral laws. The prophets did not give religious or civil laws. The reason why they dealt with moral laws was because moral laws transcend cultures and people. The law not to kill is valid in Israel as in Cameroon and the law not to commit adultery is as important in China as it is in Saudi Arabia. That is why Jesus said he did not come to abolish the law, or the bearers (prophets) of this law: moral law.
One thing you must note is that there is a clear distinction between ceremonial laws, civil laws, religious laws, and moral laws. The moral laws are the Ten Commandments, and those transcend cultures and people; whereas, the other three do not. If we practice the other three laws, then we incorporate and assimilate the Jewish life style which is not the intent of the Bible.
Jesus was for fulfilling the law, but it should go beyond the letter of the law. That is, though the Bible says give to God, you cannot give to God when your nearest neighbor has not eaten. That is why I fault people who give huge amounts of money to the church; meanwhile, their cousins are not going to school. Thus, there is no contradiction in Mk 7:9 and Mt 15:1-9.
Until then, practice true righteousness.
Prince & PA Hamilton Ayuk
“Bonyfish beware because the same net that caught the jawless fish, caught the cartilaginous fish” (Hamilton Ayuk).
Beware earthly paradise seekers because there is a serpent in every paradise"(Hamilton Ayuk).
Idle people write, idler people read, and idlest people read and whine that idle people are taking their time (Hamilton Ayuk).