1 Corinthians 1:10 (NIV)
10 I appeal to you, brothers, in the name of our Lord Jesus Christ, that all of you agree with one another so that there may be no divisions among you and that you may be perfectly united in mind and thought.
The first problem Paul identifies in his church is division (verse 10). Paul had heard reports that there were factions and cliques within the church. People's allegiance to certain individuals or groups in the church was stronger than their allegiance to the church as a whole, and this resulted in unhealthy quarrels, politicking and disunity.
How do you know if you're part of a clique? Here are a few clues:
1. you mostly talk or hang out with a certain group of people and are unfriendly toward people outside that group
2. when a church meeting is over, you immediately find your friends and ignore the people who are new or alone
3. the group you hang out with does not go out of its way to welcome and include new people
4. you only talk and interact with people that you like and don't bother reaching outside of that comfort zone
There's nothing wrong with being closer to certain people in the church than others. It's healthy and important to have good, close friends we can confide in and whose presence we particularly enjoy. It's impossible and unnecessary to be best friends with everybody.
That said, the longer you've been at a church, the more you need to go out of your way to welcome and include those who are not necessarily part of your closest circle of friends. Not just say hi, but really include them.
That's what God did for us: when we were left out in the cold, far from the presence of God, the Trinity -- Father, Son and Holy Spirit -- didn't stay in their clique. Rather, all three Persons of the Trinity reached out to us. The Father sent the Son, who gave His life for us, and then promised the Holy Spirit to us, so that we could be included in the fellowship that they have: "I in them and you in me", as Jesus says.
What if you find that others around you are acting "cliquey"? Don't worry about it. As a follower of Jesus, simply love everyone and stay alert especially for those who are alone or "on the outside" looking in. God will provide you with the friendships you need as you seek His kingdom first and live your life unselfishly.
As Paul prayed for the church in Corinth, may there be no divisions among us and may we be perfectly united in mind and thought. Let's go out of our way to welcome and include those who are new or alone, so that at Thrive no one is standing by themselves.