Acts 2:42-43 "They were continually devoting themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer. 43 Everyone kept feeling a sense of awe; and many wonders and signs were taking place through the apostles."
As we turn our attention today to those earliest days of the church, we read the following statement in Acts 2:42 regarding what the early church did in the wake of the Holy Spirit's arrival at Pentecost and Peter's preaching about that event: "they were continually devoting themselves to the apostle's teaching....". As the first Christians began to grow in doctrine, fellowship and prayer, verse 43 states: "Everyone kept feeling a sense of awe"
The early church was a church that gave themselves to the Apostle's teaching. It can be said that the early church's commitment to the Apostle's teaching was another way of describing them being saturated with the scriptures. The early Christians were not only practical and spiritual but also doctrinal. Doctrine dominated the early church's thinking, practice and spirituality. Author David Wells writes about the significance of doctrine in the life of the church in his book "No Place for Truth", page 103: No one who is familiar with apostolic teaching and practice could imagine that a bare, credal orthodoxy alone is being advocated in these passages. It is clear, for example, both from the structure of many of Paul's letters and from his many specific statements, that he saw belief and practice as inextricably related to each other, the former being the foundation of the latter and the latter being the evidence of the outworking of the former." Wells then later adds: "The apostolic exposition of God, his character, his acts, and his will (especially as these were focused in the giving of His incarnated Son) for the foundation without which one cannot have the Christian faith."
What exactly defines the "Apostle's teaching" or "content of faith"
So when we read such statements as the early Christians continually devoting themselves to the Apostle's teaching, where does one find out what they taught. Thankfully the search is not a hard one. With the same chapter, Acts 2, we find the first sermon ever preached in that early church - Peter's inaugural sermon on the Day of Pentecost. Everything he preached in that sermon comprises nearly every core doctrine and teaching found throughout the Old Testament, stated specifically by Jesus in the Gospels and spelled out completely by the Apostles throughout the rest of the Book of Acts, the Epistles and Revelation.
The contents of the apostolic teaching which shaped and defined the early Christian faith is the same teaching that acompananies the faith of Christians over 2,000 years later. By mainly looking at Peter's Sermon in Acts 2:14-40, we can list the major points and doctrines preached to his audience on the day of Pentecost, notice:
1. Authority of scripture. Acts 2:14-21; 25-28; 33-36
We can see the commitment to the Old Testament scriptures as indicated by the various quotations made by Peter. Furthermore, since Peter's sermon is recorded and included in Luke's Gospel by Divine inspiration, by default this includes the New Testament. This demonstrates that the scriptures gave birth to the church and not the reverse.
2. Jesus Christ
Peter preached that Jesus is God (2:34); incarnated in human flesh as a man who lived, was crucified, buried and risen from the dead (2:23-24) and ascended into heaven (2:34-36). Later on the Apostle Paul in his sermon on Mars Hill preached similarly and remarked in Acts 17:31 regarding the Second Coming of Jesus in judgment.
3. Sovereignty of God.
We see this truth expressed by Peter in the terms "purpose" and "foreknowledge" in Acts 2:34.
4. The Holy Spirit.
In Acts 2:33 we see reference to the Holy Spirit in terms of His Person and work: "Therefore having been exalted to the right hand of God, and having received from the Father the promise of the Holy Spirit, He has poured forth this which you both see and hear." Incidently this remark by Peter serves as initial evidence for what would be the later New Testament expression of God being One God existing as Three Persons: Father, Son and Holy Spirit.
Acts 2:38-41 summarizes the earliest preaching of the Gospel following Jesus' ascension - namely salvation by grace alone, through faith alone in Christ alone. Clearly the 3,000 that got saved in Acts 2:41a were baptized to express publically before many witnesses the miracle work of salvation wrought by the Spirit in their hearts by faith and repentance.
Acts 2:42-46 serves to underscore the necessity of church life for the believer. Without expanding into too much detail, suffice it to say that the believer's connection to the local church is considered at the heart of apostolic teaching and thus the Christian faith.
7. Great Commission.
Acts 2:47 records that many more people were being added daily to the church, which indicates that God was doing so through the witness of the early Christians.
8. The Second coming.
This final truth is alluded to in Acts 2:20-21 and 2:34. Jesus is returning back a second time to redeem His bride the church and judge the world.
Final thoughts: Why doctrine is important for the Christian life
David Wells spells out why doctrine is so vital for the Christian life in his book: "No Place for Truth", page 103: "it is this message that is our only ground for hope (Titus 1:9) and salvation (1 Corinthians 15:2; 1 Peter 1:23-25). Without it, we have neither the Father nor the Son (2 John 9). Indeed, Paul says that we can grow in Christ only if we stay within this doctrinal framework, for its truth provides the means of our growth (Col 2:6). It is no wonder that Christians are urged not to depart from the apostolic teaching they received in the beginning (John 2:7,24,26; 3:11) or from what they had heard (Hebrews 2:1), for it is the "faith once and for all entrusted to the saints" (Jude 3). May we recognize this significance and do exactly what the early church did: "continually devote ourselves to the Apostle's teaching".