Jesus gave this parable about what comes out of a man and eating with unwashed hands after upbraiding the Pharisees and scribes about upholding traditions. He was concerned about matters of the spirit and not physical issues. Eating with unwashed hands was about a physical issue, but it is what comes out of a man that proceeds from the heart that is the real issue.
There are many things that man believes to be sin which are not. The Pharisees were so steeped in their human traditions that they took offence at the disciples for eating with unwashed hands. They considered this a transgression of the tradition of the elders and equated that with sin. But Jesus showed clearly this was not the case. It is what comes out of a man that will defile him. For all sin proceeds from the spirit of a man, from his heart and soul, and it is sin that defiles a person.
The disciples did not understand this parable so Peter asked the Lord to explain it to them. The Pharisees were focussed on what goes into a man, that is, food. They believed that it was unclean to eat with unwashed hands for the food would be contaminated in some way. While we know today about issues of bacteria, salmonella and the like, we do not wash before eating as a religious tradition like the Pharisees did, but for hygiene reasons. Even then, if we did not wash before eating in most circumstance we would not suffer any harm, and certainly it is not a sin.
So it is not what goes into a man that is an issue but what comes out defiles a man. Jesus listed all manner of evil, the primary concern being evil thoughts. Evil thoughts in particular are at the root of what comes out of a person and defiles them. In other scriptures when the Lord says, “You shall know them by their fruits,” he is saying to watch and see if what comes out defiles a man or if what comes out is good fruit.
In speaking of the false teaching that the Pharisees were promoting based upon their human traditions, Jesus counselled the disciples to “Leave them alone; they are blind guides. And if a blind man leads a blind man, both will fall into a pit.” (Verse 14) He was saying that they are spiritually blind for they put their traditions above the word of God. While there are some traditions that are harmless and some that were delivered to us to keep by the Lord himself, any time we put a tradition or any false teaching ahead of the word of God we are in peril of being a blind guide.
Spiritual blindness is worse than physical blindness for it clouds and darkens the spirit of a man and leads him astray. Succumbing to spiritual blindness will cause people to fall away from following the Lord and wandering into error. Thus as the writer of Hebrews counsels, “Therefore we must pay the closer attention to what we have heard, lest we drift away from it.” (Hebrews 2:1) Whatever we hear from other people we need to weigh against the scripture and the words of Jesus to see if it accords with the truth of the gospel of Christ. To do that we need to study the scriptures so that we are immersed in it and can more quickly pick the error from the truth. As Paul wrote, “so that we may no longer be children, tossed to and fro and carried about with every wind of doctrine, by the cunning of men, by their craftiness in deceitful wiles.” (Ephesians 4:14) Only by doing this in combination with Christian fellowship and prayer are we able to ensure we are not swayed by false doctrine and the teachings of blind guides.