1st CENTURY CHRISTIANS STILL SERVING IN THE 21st CENTURY
"Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the Lord your God which I command you." Deuteronomy 4:2
The first Christians observed the Lord's supper, the communion of the body (the bread) and the blood (fruit of the vine) of Christ (1 Corinthians 10:16) during the worship service. They were to eat in remembrance of Jesus' death for mankind's sins on the cross until He returns (Mat. 26:26-28; 1 Corinthians 11:23-28). How often do we observe the Lord's supper? We follow the example of Paul and the other early Christians, who came together on the first day of the week steadfastly (Acts 20:7: Acts 2:42).
Also, on the first day of the week the disciples were commanded to give back to God as they had been blessed by Him (1 Corinthians 16:1-2) for the work of the church. They gave willingly and cheerfully (2 Corinthians 9:1-7). We follow their divine example.
We know from Acts 20:7 that they had preaching during their worship services in which God's word should be preached (2 Timothy 4:1-5). We have preaching at our worship services just as they did, teaching God's word and only His word (2 Timothy 3:14-17; Galatians 1:8-9).
God speaks to us through His word (2 Timothy 3:16-17). We speak to Him by praying through His Son Jesus Christ (Ephesians 5:20; Col. 3:17). The first disciples prayed when they met together (Acts 2:42). As the Lord commands (1 Timothy 2:1-5; 1 Thessalonians 5:17), so we do.
We also sing praises to God when we meet together as God has commanded (Ephesians 5:19; Colossians 3:16). Whatever one does in worship, it must be done only as authorized by the Lord (Colossians 3:17), in His name (by His authority) and must be done as His word directs (John 4:24). Jesus and His apostles sang (Matthew 26:30, Mark 14:26). In the New Testament, only singing (without mechanical instruments) is ever mentioned in the worship of the church (Acts 16:25; Romans 15:9; 1 Corinthians 14:15; Hebrews 2:12; Hebrews 13:15; James 5:13). For almost 1000 years from the time of Christ, singing was done without the instrument, "a cappella", or "as in the chapel". God's word has not changed since the first century, so we continue to sing without musical instruments (Acts 17:24-25) as directed by His word (Romans 14:23).