Now when they heard this, they were cut to the heart, and said to Peter and the rest of the apostles, “Men and brethren, what shall we do?”
Then Peter said to them, “Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit.
For the promise is to you and to your children, and to all who are afar off, as many as the Lord our God will call.”
And with many other words he testified and exhorted them, saying, “Be saved from this perverse generation.”
Then those who gladly received his word were baptized; and that day about three thousand souls were added to them.
And they continued steadfastly in the apostles’ doctrine and fellowship, in the breaking of bread, and in prayers.
Acts 2:37-42

But what does it say? “THE WORD IS NEAR YOU, IN YOUR MOUTH AND IN YOUR HEART” (that is, the word of faith which we preach):
that if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved.
For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation.
For the Scripture says, “WHOEVER BELIEVES ON HIM WILL NOT BE PUT TO SHAME.”
For there is no distinction between Jew and Greek, for the same Lord over all is rich to all who call upon Him.
For “WHOEVER CALLS ON THE NAME OF THE LORD SHALL BE SAVED.”
Romans 10:8-13

For Christ also suffered once for sins, the just for the unjust, that He might bring us to God, being put to death in the flesh but made alive by the Spirit,
by whom also He went and preached to the spirits in prison, who formerly were disobedient, when once the Divine longsuffering waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight souls, were saved through water.
There is also an antitype which now saves us—baptism (not the removal of the filth of the flesh, but the answer of a good conscience toward God), through the resurrection of Jesus Christ,
1 Peter 3:18-21