We need to walk right with God. No matter what we do, how much we serve, at the end of the day, it must bear out from our relationship with God. Serving the church hard without walking right with God will summount to nothing at the end of the day.
Paul said in 1 Corinthians 9:27 that he does not desire to be disqualified from the prized after preaching about the gospel. He understood the imprtance of keeping his personal faith in God.