Fellowship is an important concept in the New Testament. The Greek word translated “fellowship” is koinonia, and it occurs in some very pivotal verses. Like many other Greek words, it has several meanings that overlap to some extent. Koinonia can refer to intimate participation and full sharing with others, such as in the verses that speak of our “fellowship” with Jesus Christ (1 Cor. 1:9; 10:16). It can refer to the sharing of our lives with one another (Gal. 2:9). It can also refer to sharing in a more limited sense, such as our sharing money or material goods with others (Rom. 15:26, “contribution”; 2 Cor. 9:13).
In this article we will limit our discussion to fellowship with God, Christ, and others. In that context, many lexicons define koinonia something like, “association with others that has close mutual relations and involvement.” The Internet encyclopedia “Wikipedia” adds the important word “intimate,” in its definition, reading, “communion by intimate participation.” Perhaps a very good definition would be, “intimate joint-participation.” The word “intimate” in this definition is important, because it brings in an aspect of personal openness that might otherwise be missed. Someone once defined “intimacy” as “in to me see,” which is accurate and clear. It is amazing the extent to which we can be with others and never let them see into us. Many people can talk for hours without ever letting the listener “see” into them. That may be wise to do “on the street,” but it is certainly not how fellowship, koinonia, is supposed to work among Christians.
Intimate joint-participation with others
As we just saw above, koinonia is intimate joint-participation. Interestingly, koinonia is never used in the New Testament to describe a meeting. That is in sharp contrast to the Christian Church today, because people of many denominational backgrounds say they are “going to fellowship,” when they mean they are “going to a meeting.” In fact, this modern definition of “fellowship” has become so prevalent it has made its way into some dictionaries.
It is easy to see how koinonia, intimate joint-participation, would become the name for the meeting where intimate joint-participation occurs. In biblical times a person might say, “I am going to fellowship—to intimately participate with others.” Today the definition has shifted and the person might say, “I am going to fellowship—the place where intimate participation occurs.” There is no fundamental problem with that linguistic development. There is a problem, however, with what came to be the next linguistic step, which was that “Fellowship” eventually became the name of the meeting even if “intimate joint-participation” did not occur. Thus in some circles, the concept of intimately and jointly participating with others was replaced by just going to a meeting, which often was more of a duty than a blessing.
God has called Christians to “fellowship” with each other; to fully and intimately participate in each other’s lives, and new Christians in the early Church were glad to do that.
Acts 2:42 (NASB) 
They were continually devoting themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer.
Most of the Christians that Acts 2:42 refers to had a lot of learning and growing to do. They had been among the numbers of Jews who had rejected Jesus when he was among them, and they needed to shed many preconceived ideas about the Messiah and learn how to walk by the gift of holy spirit they received when they got born again. These Jews knew that the best way to learn and grow was to be part of a small group where they could listen intently, ask questions, dialogue with elders in the faith, share what they believed and get confirmation or correction about it, and learn how to go out into the world and be effective ambassadors for Christ.
One of the nice things about clearly understanding that “fellowship” is intimate joint-participation, or “full sharing,” is that we instantly know if we are doing it. If we arrive home from a Christian gathering and someone asks us if we had intimate joint-participation, we would not have to say, “I’m not really sure, I will have to think about it for awhile.” There is great profit and growth when we get to share with other Christians, who we are, what we believe, and what we plan to do for the Lord. Therefore, if we are not part of a group that allows us to actually “fellowship,” engage in intimate joint-participation, we should seek one out and become a part of it. Thankfully, Jesus told us that such a group does not have to be large.
For where two or three come together in my name, there am I with them.
Although most of us like Christian meetings that are more than two or three people, if we take the time to think about it, sometimes our most intimate joint-participation takes place in small meetings. We know that Jesus must have had some wonderful times with just the twelve apostles, and if there are lots of people in a meeting it is hard to have genuine intimate communication. The home churches in Acts were the perfect size for intimate joint-participation, and that is surely one reason why first-century Christians seemed to grow so quickly in the faith.
Intimate joint-participation with God and Christ
One of the more subtle aspects of intimate joint-participation that occurs in the Christian faith happens between God, Jesus Christ, and each believer. The Bible assures us that fellowship with God and Christ are part of the Christian life.
1 John 1:3b
…And our fellowship [koinonia] is with the Father and with his Son, Jesus Christ.
The spiritual life of the committed Christian should involve constant communication with God and Christ. In fact, if we could print out the daily communication between a committed Christian and God and Christ and read it, it might be quite revealing, possibly even humorous. We can talk to them, pray to them, express concerns, ask questions, bargain with them, make demands, and share with them our most intimate wishes and fears. We can also share with them exactly who we are and how we feel. True fellowship involves being in two-way communication where both parties are concerned about the mutual benefit of each other.
Although there will be times in the life of almost every committed Christian that God makes His presence known in an unmistakable way, much of the time God’s actions in our lives are more like the “gentle whisper” that Elijah heard (1 Kings 19:12). Nevertheless, we can trust the Word of God when it says that God is at work in us both to want to do, and to do, His good pleasure. Unfortunately, a very important verse on this subject is not clear in many versions.
Philippians 2:13 (KJV)
For it is God which worketh in you both to will and to do of his good pleasure.
The specific use of “will” that appears in the KJV and many other versions is not common in our vernacular, so the verse becomes unclear. “Will” is a translation of the common Greek verb thel?, and it means “to want, to desire.” The New Living Testament gets the sense of thel? very nicely:
Philippians 2:13 (NLT) 
For God is working in you, giving you the desire and the power to do what pleases him.
Most people know that God works in their lives. But here is a verse that says that God works in us so we even want to do His will in the first place—it is God who is “giving you the desire.” Also, the word “do” is the common Greek verb energe?, which means to work, act, or do. Both thel? and energe? are present tense, active voice, which means that the action is ongoing. God and Christ are always at work in us. They never leave us or forsake us. Thus, we might translate the verse: “for it is God who is continually working in you both to want to do, and to do, his good pleasure.”
Talk about intimate joint-participation! God and Christ are always participating in our lives so we will want to do, and do, the will of God. Sometimes we refer to the gentle guidance of God in our lives as “the leading of the spirit.” Christians trying to live their faith must strive to learn how to become quiet on the inside and work more and more in concert with God and Christ, enjoying the fellowship with them. In contrast, carnal Christians seek worldly pleasure by indulging the flesh, and thus are always fighting the influence of the spirit. Every Christian has to fight his flesh and sin nature, but we do not have to give in to it (Gal. 5:17). God and Christ are always influencing us to be godly, and our flesh and sin nature are always influencing us to gratify our sinful cravings. The wise Christian learns how to walk more and more in intimate joint-participation with Christ and not fulfill sinful cravings.
God knows that when Christians are deeply connected with Him and with other Christians on a heart level it is healing, rewarding, and empowering, so He made intimate joint-participation with Him and other Christians a foundational part of the Christian faith. Now each Christian has the joy and privilege of learning to tone down the influences of the flesh and to experience true fellowship with God and with Christ. When it comes to our relationships with other Christians, we have the blessing and freedom to seek out other Christians with whom we can truly “fellowship,” that is, enter into intimate joint-participation that will enrich each of our lives, help our walk, and contribute to our walking before the Lord at our full potential. Let’s not just “meet,” let’s “fellowship.”