Many years before Jesus lived, the prophet* Ezekiel* called Israel* to turn away from idols* and return to honor* God again. He talked about a day that would come in the future. God would make a new promise to Israel. He would give the people a new heart. Then they would not follow other gods. They would follow God because this would be the desire of their new heart.
The word ‘heart’ can mean the center of anything, like the heart of a city. But most of the time, the word ‘heart’ speaks of the center of a person. That is not the middle of a person’s body. But the center of ourselves. The heart is where we think and feel and decide. It is also the place of our wishes and desires. Our heart is where all of our actions begin, whether they are wise or foolish. Before we come to know God, our hearts are full of evil* thoughts. We do not honor God in our hearts. And it leads us to speak and do bad things. Our heart is selfish, proud, and does not look for God.
When a person comes to trust Jesus, God changes his heart. Like Ezekiel told the people long ago, God ‘removes our heart of stone and gives us a heart of flesh.’ He compares a heart that rebels against God to stone. A heart of stone cannot love God or respond to God. But when God rescues us, he gives us a heart that can respond to God. This new heart can seek God and desire to do as he asks. Now we can love the Lord* with all of our heart.
God gives us this new heart so that we can be holy. The word ‘holy’ means to be set apart. The scriptures* tell us that God is holy. That means that God is like no other person or angel.* God is separate from any sin* or wrong or anything that is not pure.
When the word is used for people or things, it speaks of something that is set apart for God. It means to be set apart for a special purpose. When God chose Abraham’s* children to be His chosen nation, he called them to be holy. He wanted the nations near them to see that they were not like any other people. They belonged to God. When God told Moses* how to build the Tent of Worship*, he told him that the place would be holy. It would be set apart for a special purpose, a place that belonged to God. He told him to make things that would be used in this holy place. He called them holy as well. That meant that these things were to be used only in the holy place and only in the way God had said. The priests* who would serve the people were also called holy. They were the only people that could do the special things God had for them to do. They were set apart by God.
The New Testament* uses the word ‘holy’ to talk about the people who have believed in Jesus. When we trust Jesus, he gives us a new heart. And he sets us apart for himself. We become part of the new and holy nation of those God has chosen for himself. He gives us the Holy Spirit. And the Holy Spirit changes our hearts from having a desire to sin to having a desire to please God. So, our old hearts are changed. We love God, more and more. Our bodies are also set apart to be holy because now, the Holy Spirit lives in us. So, we act in ways that are not like the world around us. We use our bodies to show that we belong to God. We present our bodies to God. We are led by the Holy Spirit to do the things he wants us to do. We learn and love God’s word. We spend time with other Christians. We worship and pray with them.
We want to use our bodies to do the things that please God. When we find anything in our hearts that would not please God, we turn from it. We work to become what the Holy Spirit is changing us to be. So, we work to be holy in everything we do. The Holy Spirit works in our new hearts to make us more and more like God’s holy Son, Jesus.
 Ezekiel 36:26; compare Jeremiah 31:33
 Proverbs 16:18; Jeremiah 17:9-10; Matthew 15:18-19; Romans 1:21-25
 compare Zachariah 7:12
 Leviticus 19:2; Isaiah 6:3; Isaiah 43:15; Revelation 4:8
 Romans 6:13; Romans 12:1; 1 Thessalonians 4:4
 Philippians 2:12-13
 Hebrews 12:14; 1 Peter 1:15