Answer: The word Corban is found only in Mark 7:11 in the King James Bible. The word itself is of Hebrew-Aramaic origin (Strong's Concordance #G2878) and means a votive offering or a gift consecrated to the funding of the temple. Thayer's Greek Definitions states that it is a gift offered to God through the temple's sacred treasury.
What kicked off the Bible's unique New Testament discussion of Corban found in Mark 7? It started when some self-righteous Jewish religious leaders noticed that some of Jesus' disciples did not ceremonially wash their hands before eating. They believed that the absence of such an act made their hands "defiled" and therefore unfit to use for eating (verses 1 to 5).
The Jews' ritualistic washings, which started out as man-made traditions, were eventually elevated to be as binding on a person as God's written laws! The outrage of the leaders that such a practice was abandoned by the disciples motivated them to complain to Jesus. His response, however, was a scathing condemnation of their hypocrisy of which Corban was only one of many such examples.
And He answered (Jesus) and said to them, "Well did Isaiah prophesy concerning you hypocrites, as it is written, 'This people honors Me with their lips, but their hearts are far away from Me. But in vain do they worship Me, teaching for doctrine the commandments of men'" . . .
"Full well do you reject the commandment of God, so that you may observe your own tradition . . .
"For Moses said, 'Honor your father and your mother'; and, 'The one who speaks evil of father or mother, let him be put to death.' But you say, 'If a man shall say to his father or mother, "Whatever benefit you might receive from me is corban" (that is, set aside as a gift to God), he is not obligated to help his parents'" (Mark 7:6 - 7, 9, 11 - 12, HBFV).
Jesus condemned the religious leaders' enforcement of what was clearly a non-Biblical practice as if it were given by God and binding on all those who worshipped him!
How common was it?
The Treasury of Scriptural Knowledge (TSK) states that the practice of Corban was common among the Jews. The Pharisees would release, by their own authority, a child from supporting his parents. Amazingly, according to the TSK, these religious leaders would deem it sacrilege if such a person afterwards decided to go ahead and support those who gave birth to him!
Easton's Bible Dictionary states that a person could not reclaim anything designated as Corban. Jesus hated this practice of the Pharisees, as their traditions in this area nullified God's commandment that children should honor their parents. Their man-made teaching gave people an excuse for not helping their father or mother. It also, at the same time, offered them the opportunity to use such designated good for their own selfish use.
Why is it wrong?
God instituted the fifth commandment for the explicit purpose of honoring one's parents (Exodus 20:12). Unfortunately, human beings have consistently tampered with his instructions and Corban is just one of many cases. One of the ways to honor parents is by giving them financial support when in need, especially when they are in old age.
Children were obliged to adhere to the law whether they loved their parents or not. However, with the permission of the Pharisees, they could circumvent part of the law by dedicating money meant for the parents to the temple through Corban. This is one example of how the Eternal's laws were made "of no effect" and overridden by religious tradition.
Spirit of the tradition
Sadly, the practice of Corban is alive and well in some modern Christian groups. Some churches are known to encourage members to place a higher priority on the "needs" of the church above their God-given responsibility to their parents and family.
Some organizations and outreaches have been known to pressure their members, on a regular basis, to give such large amounts of money "for the sake of the gospel" that it leaves little if any support remaining to aid needy parents. Whether in the ancient world or in modern times, the Bible clearly condemns the greedy spirit of Corban.