Nobody likes to be served on a plate that contains fragments of a previous meal eaten by a stranger, or a cup with lip and finger prints smeared around the rim. We muse that, if those dishes are dirty now, it follows that the food which comes out of them may be tainted and unfit for our consumption—those fragments could make us sick.
In the Bible, our Lord compared the religious leaders of His day (Pharisees) to dirty dishes: “Woe unto you, scribes and Pharisees, hypocrites! for ye make clean the outside of the cup and of the platter, but within they are full of extortion and excess. Thou blind Pharisee, cleanse first that which is within the cup and platter, that the outside of them may be clean also. (Matthew 23:25-26)” His point was that good deeds and keeping creeds were of no value if they were not performed first in the heart. As a matter of fact, God keeps His eye on the heart of man. “…man looketh on the outward appearance, but the LORD looketh on the heart. (1Samuel 16:7)”
God knows that if a person believes and thinks pure and wholesome thoughts within, what he does and says without will be pure and wholesome as well. On another occasion He told these filthy leaders, “O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh. (Matthew 12:34)”
Getting cleaned up on the inside sounds logical, but it is nonetheless impossible to clean one’s own heart because, “The heart is deceitful above all things, and desperately wicked: who can know it? (Jeremiah 17:9)” The Psalmist prayed, “Search me, O God, and know my heart: try me, and know my thoughts: And see if there be any wicked way in me, and lead me in the way everlasting. (Psalm 139:23-24)”
If you desire to be clean within and without before God, you will need help—you’ll need Jesus. “…and the blood of Jesus Christ his Son cleanseth us from all sin. (1John 1:7)” “Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost; (Titus 3:5)”