After Chrsit had left the earth, His Apostles were responsible with the charge to keep the faith and to make new disciples. As this process began there was much opposition to the cause.
Today, many of us do not face persecution, but the sad fact is that a lot of us of gone "Lone Wolf." We have decided that we have Jesus and He is all we need. Unfortunately this is not what the Bible teaches, nor is it what the early church practiced.
Acts 2:42 shows that they continued (after receiving the Holy Spirit) to meet together to study the Word, and have fellowship. Hebrews 10:24-25 shows us that not only are we to continue to meet, we are to build one another up and help each other in our daily walk.