"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 shall receive the gift of the Holy Spirit. For the promise is to you and to your children and to all that are far off, every one whom the Lord our God calls to him." And he testified with many other words and exhorted them, saying, "Save yourselves from this crooked generation." So those who received his word were baptized, and there were added to their number that day about three thousand souls… …praising God and enjoying the favor of all the people. And the Lord added to their number daily those who were being saved."
The crowd is confronted with the fact that the very Messiah that they have long awaited has been rejected and murdered some 50 days beforehand. Perhaps there were some in this crowd that were even present during the day Christ was crucified. They were cut to the heart and in turmoil. They realized the terrible mistake they had made and were fearful of the precarious position in which they were now in. In verse 37, they asked, “What shall we do?” They had just heard Peter, in the language of Joel, speak of a possible salvation; and the question, “What shall we do?” indisputably means, What shall we do to be saved?
Peter tells them to repent, each and every one of them. He tells them to be baptized in the name of Jesus Christ for the forgiveness of your sins. Some translations actually render this --so that your sins will be forgiven. He tells them this is for every one of them. He tells them that if they do this they will receive the Holy Spirit. He tells them this is a promise of God. He tells them this promise of God is for them. He tells them this promise of God is for their children as well (meaning it is for all generations). Peter tells them very clearly and carefully this promise is not just for them, but for all that are far off—this is God’s plan of salvation for everyone for all generations everywhere, for all time. (This applies to us today. God’s salvation plan is still the same for us today as it was when Peter spoke these words to this crowd. It has not changed.) For further emphasis he tells them this promise of God is for everyone whom the Lord our God calls to Him. Peter continues with many other words and urges them to heed his words and to save themselves from this evil generation (This statement of Peter confirms undeniably that he was speaking to people who were NOT saved). And those that accepted his words were baptized and about 3,000 souls were saved that day. This is God’s salvation plan in a nutshell. This is the new birth Jesus spoke of in John 3:5
"Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God."
With repentance and faith (belief) in Jesus the Son of God who died for our sins and was raised from the dead, God promises to forgive our sins (each and every one of them, past, present, and future) and give us the gift of the indwelling of the Holy Spirit when we are baptized into His Son, Jesus Christ.
Notice verse 42 says the believers continued steadfastly in the Apostle’s doctrine. What is the Apostle’s doctrine? Peter just told us in the previous verses (v.38-39). Notice also the phrase, “added to their number” -- how it is associated with the word “baptized” in verse 41 and then in verse 47 it is associated with the words “being saved.”
For Further Study:
James 1:22 says,
“Do not merely listen to the word, and so deceive yourselves. Do what it says.”
How would you “do what is says” in regards to Acts 2:38?