There is no point in following a person who does not know where they are going. Jesus accused the religious leaders of being 'blind guides'. He also called them 'blind fools' because they did not understand how to handle truth themselves, and so could not teach truth to others. The issue in question was about swearing. Because so many people tell lies, swearing has become a method of reassuring people that what is said is true.
 
However they had developed swearing as a fine art. They said that to swear by the temple has no binding effect but to swear by the gold of the temple did bind the person to their promise. Jesus said that was nonsense: how can the gold of the temple be greater than the temple itself? Likewise how could the gifts offered on the altar be greater than the altar itself?
 
Jesus said that every promise should be kept because God is the judge and knows all things. The attempt to appear sincere in what they were saying while knowing that they had no intention of keeping their promises, was rank hypocrisy. Not only were they dishonest and manipulative, but they could not even see that their integrity had evaporated and they were morally corrupt. Jesus had already told the disciples that they should never swear to affirm that they were telling the truth (Matthew 5:33-37). In the future, as church leaders, the disciples needed to be people of their word, whose promises would be carried out and whose teaching would always be true.
 
There are no 'white lies': they are all lies. There are no 'half-truths' they are always lies. Indeed the most manipulative lies have a lot of truth in them, but they are not wholly true. Swearing to establish truth is an admission that the person cannot be trusted; you never know what is true and so you are foolish to follow them. If you have spiritual responsibility you must train yourself in the truth, understanding it, doing it and teaching it ... in the church, in the workplace and in the home. Swearing blind is not a mark of integrity but of folly. Do not appoint such a person to spiritual office, wait until you see what they are really like (1 Timothy 5:22, 24-25).