This is one of the most important questions for a Christian or anyone to understand. About 2000 years ago, Jesus Christ addressed the crowds on this very topic because even then it was a problem between the Pharisees and other Jews. The Pharisees taught that eating with unwashed (or unbaptized) hands defiles a person, by making them “unclean, polluted, and desecrated.” Jesus said their religion couldn’t purify the real problem.
Then Jesus called to the crowd to come and hear. “Listen,” he said, “and try to understand. It’s not what goes into your mouth that defiles you; you are defiled by the words that come out of your mouth.”
Then the disciples came to him and asked, “Do you realize you offended the Pharisees by what you just said?”
Jesus replied, “Every plant not planted by my heavenly Father will be uprooted, so ignore them. They are blind guides leading the blind, and if one blind person guides another, they will both fall into a ditch.”
Then Peter said to Jesus, “Explain to us the parable that says people aren’t defiled by what they eat.”
“Don’t you understand yet?” Jesus asked. “Anything you eat passes through the stomach and then goes into the sewer. But the words you speak come from the heart—that’s what defiles you. For from the heart come evil thoughts, murder, adultery, all sexual immorality, theft, lying, and slander. These are what defile you. Eating with unwashed hands will never defile you.” (Matthew 15:10-20)
And then he added, “It is what comes from inside that defiles you. For from within, out of a person’s heart, come evil thoughts, sexual immorality, theft, murder, adultery, greed, wickedness, deceit, lustful desires, envy, slander, pride, and foolishness. All these vile things come from within; they are what defile you.” (Mark 7:20-23)
These are the things which defile a man,…. These are filthy in themselves, and must pollute all in whom they are; they bring a defilement on the whole man, both body and soul, fasten guilt upon him, and expose him to everlasting punishment: but to eat with unwashen hands defileth not a man: should a man neglect to wash his bands before eating a common meal, this need give him no uneasiness; he contracts no filth to his soul hereby, nor any guilt to his conscience; nor does he break any law of God; nor is he liable to any penalty for such an omission. This is a trifling matter, and merits no regard; but the things before mentioned are in their nature evil: they are contrary to the law of God; they are abominable in his sight; they render men loathsome and odious to the divine being; and expose them to shame and ruin; and it is only the blood of Christ can cleanse them from the pollution and guilt of them, and secure them from that punishment they deserve.–Gill’s Exposition of the Entire Bible
For more than 5000 years, God has said an evil heart defiles a man
[At the time of Noah] The LORD observed the extent of human wickedness on the earth, and he saw that everything they thought or imagined was consistently and totally evil. (Genesis 6:5)
Guard your heart above all else,
for it determines the course of your life.
Avoid all perverse talk;
stay away from corrupt speech.
Look straight ahead,
and fix your eyes on what lies before you.
Mark out a straight path for your feet;
stay on the safe path.
Don’t get sidetracked;
keep your feet from following evil. (Proverbs 4:23-27)
Listen, my son, and be wise, and set your heart on the right path (Proverbs 23:19)
A good man brings good things out of the good stored up in his heart, and an evil man brings evil things out of the evil stored up in his heart. For the mouth speaks what the heart is full of. (Luke 6:45)
For more than 5000 years, the cure has always been a new clean heart
And I will give you a new heart, and I will put a new spirit in you. I will take out your stony, stubborn heart and give you a tender, responsive heart. (Ezekiel 36:26)
Create in me a clean heart, O God, And renew a steadfast spirit within me. (Psalm 51:10)
Jesus replied, “Truly, truly, I tell you, no one can see the kingdom of God unless he is born again.” (John 3:3)