The work of Christ, the work of His love for all men, that He desires to do in us and through us, is facilitated when we pay little or no attention to denominational details as we confront the world of both other Christians (many of whom are not really Christians yet) and non-Christians. Actually, it is not up to us to divide sheep from goats confessionally or morally.
When encountering other Christians, we treat them in the same loving way as Christ has treated us, welcoming them without argument (in case their faith is weak or their doctrinal understanding incomplete or erroneous), and making it known to them that if they are followers of Jesus, then they belong to the Church, and that is Orthodoxy, not denominationally (since it is no denomination), but existentially.
If a man is called to follow Jesus, and he answers that call, regardless of his understanding of it, then he is ipso facto a member of the Church, and the Spirit in us bears witness to that fact, and we must accept it. The Church in its protocols and structures will do all it can to separate the sheep from the goats, the wheat from the chaff, but that is not what the disciples do.
We are simply ambassadors, telling and demonstrating to others that the Church is love, mercy and forgiveness existentially, that it is safety, that it is welcome into the Kingdom of God, so that sensing no tollgates or border crossing officials, they can enter the court of the Gentiles where the Lord Himself can begin ministering to their inner man, bringing them gradually into the mind of Christ, being able to use us whom He has already redeemed and is fashioning into images of Himself, to transform them, adding them to our number.
This He does in spite of the Church's external forms and protocols, not because of them. The real value of the Church's constructs is demonstrated only after the genuine conversion to Christ has occurred, and the new disciple really joins us in that school of righteousness that is not an external rule forced on us from the outside, but the content of our thankfulness to the God whom we now know has really saved us.
We no longer pretend to be sinners so as to pretend to be saved. We finally know the truth, and that sets us free: free to serve the living God not according to a written law, but according to a spiritual law that is now written in our hearts and is expressed every time we do what we see Him doing.
Not by us, Yahweh, not by us, by You alone is glory deserved,
by Your love and Your faithfulness.
Psalm 115 Jerusalem Bible