Summary: Christians are expected to unite with a congregation of the faithful in order to fulfil the ministry God assigns each follower of Christ.
“Those who received his word were baptised, and there were added that day about three thousand souls.
“And they devoted themselves to the apostles’ teaching and fellowship, to the breaking of bread and the prayers. And awe came upon every soul, and many wonders and signs were being done through the apostles. And all who believed were together and had all things in common.” 
Believe it or not, there are professing Christians who reject membership in a church. I suppose these saints could give any number of reasons for not joining a local congregation, though I cannot imagine a single excuse for their refusal to unite with a local congregation. Perhaps one of the most common excuses given for refusal to openly unite with a New Testament Church is that one does not believe that the early church kept membership rolls. Such a statement is foolish, to say the least. Even a casual reading of the New Testament reveals that membership is both expected and demanded by the Saviour Who redeems His people. In order to explore this topic more fully, focus with me on the text selected for this day. It is an account of the first evangelistic crusade conducted by members of the New Beginnings Baptist Church of Jerusalem ten days after the Risen Saviour ascended into Heaven.
THOSE BAPTISED WERE ADDED … TO WHAT? Let your mind drift back to the events that marked the beginning of the first assembly arising from the resurrection of the Risen Saviour. The Master, Christ Jesus, the Lord Who Lives Eternally, had ascended into the Glory. Angels had appeared to the disciples, challenging them to do what they had been commanded to do. Together, those who dared identify as followers of The Way gathered in an upper room where they would be safe. There, they devoted themselves to prayer, “together with the women and Mary the mother of Jesus and His brothers” [ACTS 1:14].
Preparing themselves for promised blessing, the band of disciples continued in prayer for ten days, praying until the Day of Pentecost arrived. What a glorious day that proved to be for those first disciples. It was not that they did not know that the Lord Christ was powerful—they had witnessed His power demonstrated repeatedly through miracles and ultimately through His conquest over death. However, they had not personally experienced the power of the Risen Son of God. With the outpouring of the Spirit at Pentecost, power was demonstrated in each one individually and through them corporately, just as power waits to be demonstrated in us and among us to this day.
Filled with the Spirit, they began to communicate the glory of the Risen Lord to all those in Jerusalem. Peter became spokesman for the nascent church and provided an exposition of Joel’s prophecy. The result of this united revelation of God’s grace and glory among His holy people was that those hearing this message were “cut to the heart” [ACTS 2:37]. It wasn’t simply that those hearing the message were wounded, but they were compelled to ask how their culpability could be assuaged.
Peter’s response is classic, it is the only answer that will lead to life to this day. The Apostle to the Jews thundered, “Repent and be baptised every one of you in the Name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to Himself” [ACTS 2:38, 39].
Our text begins with the receipt of the Pentecostal message delivered by the Spirit-filled believers. Peter served as spokesman for those testifying to the grace of God, but all had participated in testifying to the grace of God. When they cried out for mercy, Peter pointed to Christ and open confession. Then, “Those who received his word were baptised, and there were added that day about three thousand souls” [ACTS 2:41]. Throughout the New Testament, those who came to faith were immediately baptised. There was no requirement for a “baptismal class,” no extended period of waiting, no delay until matters could be arranged to make it easy—those saved were baptised. There is no suggestion anywhere in the New Testament that anyone but baptised believers were admitted into the fellowship of the church. No one was regarded as being saved until faith was professed through baptism. This is evident through the following observations.
IT WAS TAKEN FOR GRANTED AMONG THE NEW TESTAMENT CHURCHES THAT ALL BELIEVERS WOULD BE BAPTISED. As an example of the veracity of this statement, consider ACTS 8:12. Of those responding to the message Philip preached, we read, “When [the Samaritans] believed Philip as he preached good news about the kingdom of God and the name of Jesus Christ, they were baptised, both men and women.” At the time they believed, the men and women present were baptised. There was no delay, no hesitation, no waiting until a class could be organised. They were baptised immediately!