We can sometimes have different understandings of what exactly clean looks like. A clean car, or a clean house, may look different to one person than to another. Why? Because we have different standards by which we judge whether something is clean or not. For example, a child may be perfectly happy with the state of their bedroom, and yet a parent may not. We view cleanliness with different standards in mind.
It’s the same when we come to think about us and God. Not in the sense of physical cleanness, but as clean and pure before God. What does it mean to be clean before God? And by what standard does God look at us?
And this is what is at stake in Mark Chapter 7:
14 Again Jesus called the crowd to him and said, “Listen to me, everyone, and understand this. 15 Nothing outside a person can defile them by going into them. Rather, it is what comes out of a person that defiles them.” 
17 After he had left the crowd and entered the house, his disciples asked him about this parable. 18 “Are you so dull?” he asked. “Don’t you see that nothing that enters a person from the outside can defile them? 19 For it doesn’t go into their heart but into their stomach, and then out of the body.” (In saying this, Jesus declared all foods clean.)
20 He went on: “What comes out of a person is what defiles them. 21 For it is from within, out of a person’s heart, that evil thoughts come—sexual immorality, theft, murder, 22 adultery, greed, malice, deceit, lewdness, envy, slander, arrogance and folly. 23 All these evils come from inside and defile a person.”
The author Michael Morales defines cleanness as this: Being clean is being ‘fit for the Presence of God.”
What makes a person clean or not clean before God? And what is his standard? Mark 7 shows us that it’s not what goes in, but what comes out of us. Defilement needs to be dealt with if we are to have fellowship with God. And Jesus tells us to look within, to the deeper problem of sin. Sin comes from the heart.
Jesus doesn’t let us off the hook and say, it’s just how you were brought up, it’s just where you were born, your environment. No he says, your heart is the problem. Sinclair Ferguson says, “the heart is a factory of evil. It’s corrupted and pumps sin through every area of life.” Or as Jesus says in verse 23. “All these evils come from inside and defile a person.” We have a heart problem, sin is what makes us unclean, and this is the standard that God views us by.
This is where the genius, the wonder, the glory of the gospel comes through!
Jesus is the solution to our inner uncleanness. We, all of us, need to be washed and cleansed from the inside out. He comes to fix our hearts. He is the one who declares the unclean as clean. And only he can do it.
2 Corinthians 5:21 says 21 God made him who had no sin to be sin for us, so that in him we might become the righteousness of God.
Jesus is the solution to our heart problem for he deals with the sin problem within which defiles us. He washes. He purifies. He cleanses us from our guilt before God. He was made sin for us, giving his precious blood to wash our hearts.
And so, we’re to live in this reality.
If you have been cleansed, then live clean.
If you have trusted in Jesus and declared righteous, then a life of righteousness.
If you’ve been washed, then live in a pure way.
For the work that Jesus has begun in you, he will continue and complete.
He is cleaning us from the inside out.