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 …. So those who received his word were baptized ( RSV , Acts 2:38-39 , 41 ).
“ Repent and be baptized ,” the calling of the Apostles to all of God ’ s people to come , hear and receive the Good News , created a “ religious fervor ” 8 where on that day “ about three thousand souls ” ( RSV , Acts 2:41 ) were received into the early Church through the holy Spirit , where “ they held steadfastly to the apostles ’ teaching and fellowship , to the breaking of the bread and to the prayers ” ( RSV , Acts 2:42 ). As time passed the Church grew in numbers despite ongoing persecution until Constantine became emperor , issuing the Edict of Milan in 313 AD , legalizing Christianity and naming it the religion of the State . The Church through the magisterium was now free to grow in knowledge and wisdom , to develop doctrines and dogmas . These authoritative teachings of the Church focused on the holy Trinity , the Incarnation and Mary , the Mother of God in answer to heresies of the time . The hierarchy of the Church gathered together for ecumenical councils , where orthodox beliefs and other matters regarding Church reform were discussed at length . These councils of the Church leaders led to the definitive teachings of the Church . 9
8 John Vidmar , OP , The Catholic Church Through the Ages : A History , ( N . J ., Paulist Press , 2005 ), 143 . 9 Hubert Jedin , Ecumenical Councils of the Catholic Church : An Historical Outline , ( NY : Herder and Herder , Inc .,
1960 ), 16 .