The New Testament stresses that Christians need the fellowship of others of like mind. An identifying mark of the true church is that the members have love for one another (John 13:35). Indeed, one of the criteria by which Christ will judge us is how we treat our brethren in the church (Matthew 25:31-46). How can we love and serve one another if we do not fellowship with and get to know each other?
God has given us ample instruction regarding how we should relate to other Christians. It is His purpose to teach us how to get along with each other so we can teach others about these things in the Millennium. We are to be unselfish and concerned for the needs of others (Philippians 2:4). God wants us to learn patience and forgiveness (Colossians 3:13), striving to be "kindly affectionate," humble, and self-effacing in our dealings with one another (Romans 12:10). We should be giving and hospitable to our brethren (verse 13).
The New Testament is replete with various admonitions on how we should interact with our brothers and sisters in the church. Obviously, God views our interaction with other Christians as vital to our training to become members of the God Family and qualifying for a position in His Kingdom. He wants us to develop interpersonal skills that equip us to deal with occasional differences of opinion and offenses.
Our fellowship should be a source of encouragement to one another. We should use this time to show love to our brethren and to motivate them to perform acts of kindness and service for others. All of these exhortations show a clear need for us to be part of an organization of God's people. God's Sabbath service is like a weekly training school for Christians. The spiritual food that God's true ministers prepare for us is vitally important for our spiritual growth and development. In discussing the relationship of the ministry to the church member, Paul explains that the ministry is given
for the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ. (Ephesians 4:12-13)
The interaction that we have with one another when we fellowship at church services helps us to develop the fruit of God's Spirit—love, joy, peace, longsuffering, kindness, goodness, faithfulness, gentleness, and self-control (Galatians 5:22-23). Paul shows that the church is truly Christ's body, and like the human body, each part depends upon the other parts.