Acts 2:40-42

And Peter solemnly testified and continued to admonish and urge them with many more words, saying, “Be saved from this crooked and unjust generation!” So then, those who accepted his message were baptized; and on that day about 3,000 souls were added [to the body of believers]. They were continually and faithfully devoting themselves to the instruction of the apostles, and to fellowship, to eating meals together and to prayers.