Every single Christian matters to the body of Christ.
There is only one body - one church (Ephesians 1:22-23; 4:4) - and that body is the Lord’s body.
When you heard that Jesus is Lord and Christ (Acts 2:36), believed, repented, and were baptized for the forgiveness of your sins (Acts 2:38), Jesus added you to His church (Acts 2:47).
Christians are members of the one body of Jesus Christ (1 Corinthians 12:12). We are placed in His body by being baptized (1 Corinthians 12:13).
God has set each one of us in the body of Christ as it pleased Him - we all have different things we do in the function of the Lord’s body (1 Corinthians 12:14-19).
Although we may do different things - just like a hand and a foot do different things - we all matter. We are all essential members (1 Corinthians 12:20-26). When one of us hurts, the rest of the body hurts. When one of us rejoices, the rest of us rejoice.
Why?
Because we are individual members of the body of Christ (1 Corinthians 12:27). We all matter because of Him. We all have something we can do in service of the King because of what He has done for us.
So Christian, remember that your service matters as a member of the body - the church - of Christ. Not because we are so important in and of ourselves, but because we are members of the body of Jesus.
Because of Him, we matter. Because of Him, our service has meaning and purpose (1 Corinthians 15:58).