"Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, “Brothers, what shall we do?” 38 And Peter said to them, “Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit.39 For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself.” - Acts 2:37-39
This is a recording of the impact the Spirit had on people when they heard the first sermon ever proclaimed by the Church of the risen Savior Jesus Christ. It occurred just after the Holy Spirit came upon the Apostles in the Upper Room. From beginning to end we are meant to understand that the cause behind every effect that day was the one component seemingly absent only one day before: the Holy Spirit. It is the Spirit who emboldened and filled Peter that he might preach the word; and it is the Spirit who cut the hearts of everyone the Lord our God called to Himself, and it is the Spirit who, though the word, made the response of faith in Jesus Christ certain in those He cut.
This is a profound concept. Luke is describing a moment when the Holy Spirit falls. What happens when the Holy Spirit falls on a human being? They are cut to the heart ... the Holy Spirit takes up the word of God to cut deeply (or to circumcise) the heart. The Greek word for "cut" is the word κατανύσσειν, used only here in the New Testament. The kindred noun κατάνυξις occurs Romans 11:8, in the sense of slumber (God giving them a spirit of stupor, eyes that would not see and ears that would not hear, down to this very day.”).
But here God is cutting the callous armor and deep prejudice of their hearts to reveal the soft flesh underneath generating alarm and conviction for their sin for rejecting/crucifying the Messiah. The word "cut" is passive here indicating that it is not something they are doing to themselves but is something being done to them. Many heard from Jesus and His apostles before. So what was different this time? The Holy Spirit. And their response "What shall we do" shows a beautiful childlike docility, pliable in God's hands, enabling them to discover that their whole past actions were one horrible mistake, and now they only sought with desparation to be set right with God for the future,
The idea of the word κατανύσσειν is to be cut all the way down. To be pierced through. The idea is that Spiritual life begins with a cutting ... a puncture. Before you can have something new, God must cut through something old. Not unlike a farmer who wants to plant seeds on his land and looks out to realize he must first plow up the fallow hard soil. Before I can plant a seed I must plow up that hardened soil to get at the soft soil underneath. This is what Luke is describing, a moment when God, in His grace, pours out His Holy Spirit on hearts that have been hardened to Jesus and suddenly something radical happens - a complete transformation by the Spirit of God.
Actually this is a fulfillment of one of the most important Old Testament prophesies.
"And the Lord your God will circumcise your heart and the heart of your offspring, so that you will love the Lord your God with all your heart and with all your soul, that you may live." - Deut 30:6
Using Old testament language God circumcises (or cuts) their heart.
Repeated in Ezek 36:26-27
"And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. 27 And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules."
After much talk of Israel's exile, Ezekiel ends with some good news. Promising a day in which God will miraculously work in men, to change their disposition, and its going to take place in the deepest recesses of their heart. This is a description of salvation. God, because he loves you, comes by the power of the Holy Spirit as if He sticks His hand in, as it were, to remove the heart of stone and replaces it with a new heart -- a soft heart, a heart of flesh, a heart that loves God. Its the cut of the Spirit. The bible calls it regeneration, born again, new spiritual life. Its not just improving the old house... painting the walls and putting up new curtains. No...God must go all the way down to the bottom and remove the old foundation, utterly doing away with the old house and replacing it with a new one.
People do not simply decide to take up Christianity... no it takes you up. God decides to send His Holy Spirit to make you a believer in Jesus Christ. And He does it because of His great love for you. So the cut is not a vicious one, it is a cut of love, a cut of mercy... giving us a gift we would never be able to give to ourselves.
When people hear this they often ask, how will I know if that has happened? What would the fruit be if the Spirit changed me? How would I know I have been born again, regenerated? Look to the passage. Those cut to the heart said "Brothers, what shall we do?" It was the most earnest, broken cry of the heart they had ever uttered. It came from the deepest place within them.
So how do you know? you know because when the Holy Spirit works in a heart, that heart becomes soft and willing to do whatever it takes to be right with Jesus Christ. Suddenly it goes from being hard hearted towards Jesus to "I want to do anything I can to follow Jesus, love Jesus. know Jesus ... "what should I do.. tell me what to do." That's how you will know. That is why they are ready for what Peter is going to say in verse 38 where he tells them they need to repent. If your heart is still hard and someone tells you to repent you will scoff. Hard hearted people cannot repent because repentance means I am going full throttle one way and God changes my mind and understanding to the point I can acknowledge I am wrong and need to turn around and walk after Jesus... a change of mind, a change of direction that only happens when God softens our heart. You come to the realization you have been ignoring Jesus, running from Jesus and want nothing to do with Him and then being turned come to recognize that Jesus is Lord and I need to repent. That is why repentance involves anguish about sin, deeply feeling remorse over it and openly and willingly confessing it. Saying I am broken and have sinned against You and need Christ. Therefore, to accept the humbling terms of ther gospel takes a supernatural work of the Holy Spirit. It is He who makes us humble and gives us understanding; it is he who makes us see how lovely Jesus is, and not we ourselves.
Then Peter tells the hearers, the name you have been rejecting, now take it upon public declaration in baptism - publicly declare that your life is under the grace and authority of Jesus Christ. He is Lord. God cuts your heart, you become a believer, God grants repentance from trusting in your self-righteousness and gives you a deep desire to leave your sin; He then stirrs you to love and obey Jesus and are baptized. You publicly display what has happened personally in your life. Salvation was never meant to be private but in big company. Make it known in your community and the world. This is how you know that you are among those whom God has called to Himself.
- John Hendryx
HT: Pastor Adam McMurray for help with some concepts here.