If a disciple of Christ is outside of the institutional church, does that mean there is something wrong with his or her witness before the world? I guess that would depend upon their walk in Christ. If this disciple had a love for lost souls, showed God’s judgement on sinners, tempered by His Grace and Mercy in Christ then that might be a start to know who they are in Christ. If they minister to poor, sick and destitute. If they visited their brothers and sisters in prison. In summation if they followed the Commandments of Christ as set out in the New Testament in Love, then the fruits that we see will be an indication that this brother or sister is secure in the Lord.
It all starts with fear of the Lord followed by a humble walk, knowing God has power over all. So why are the people inside the churches so concerned about us outside the camp if our heart, mind and soul are fixed on Christ?