Hearing this, they were cut to the heart and said to Peter and the other apostles, ‘What are we to do, brothers?’
‘You must repent,’ Peter answered, ‘and every one of you must be baptised in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit.
The promise that was made is for you and your children, and for all those who are far away, for all those whom the Lord our God is calling to himself.’ He spoke to them for a long time using many other arguments, and he urged them, ‘Save yourselves from this perverse generation.’
They accepted what he said and were baptised. That very day about three thousand were added to their number. These remained faithful to the teaching of the apostles, to the brotherhood, to the breaking of bread and to the prayers.
Acts 2:37-42 (New Jerusalem Bible)