There’s only ONE WAY to know if we are in the “right group”, meaning Christ’s Body. That is to study His Word to discover what true ‘righteousness’ is. Knowing ‘righteousness’ from His Word then, how can we turn to those wrong groups who oppose righteousness?
     Only one who loves our Lord Jesus, but doesn’t know what God’s Word says, could ask such a question as this one. That question shows a type of ‘fear’, as if one was pre-ordained to messing-up. Even the ‘workers of iniquity’ can change, using their free-will, to come to Christ Jesus, and become a ‘son of God’. Remember Isaiah 1:19 that IF we are “willing and obedient, ye shall eat the good of the land.”? That’s the condition; “IF” we are “willing” to be obedient to Christ our Lord.

James 3:13-18
13    Who is a wise man and endued with knowledge among you? let him shew out of a good conversation his works with meekness of wisdom.
14    But if ye have bitter envying and strife in your hearts, glory not, and lie not against the truth.
15    This wisdom descendeth not from above, but is earthly, sensual, devilish.
16    For where envying and strife is, there is confusion and every evil work.
17    But the wisdom that is from above is first pure, then peaceable, gentle, and easy to be intreated, full of mercy and good fruits, without partiality, and without hypocrisy.
18    And the fruit of righteousness is sown in peace of them that make peace.
(KJV)

     We are to ‘make peace’ in the world for our Lord, with His Guidance. And that doesn’t mean just ‘laying down’ either, but being a bit ‘salty’ for our Lord. But we are to try to make peace whenever possible. If that means we go to ‘jail’ for making peace and following Christ Jesus, then so be it. We are not to fear this flesh world, but be strong ‘overcomers’. Just believing on Christ as Savior is no guarantee that we will go through life with no trials. The matter is, everyone, those in Christ, and those not in Christ, all must suffer through various trials while in this flesh. My question is, which is easier; to go it alone, trying to make our own decisions and choices without God in our lives, or to ask Him to come in our lives? When we do seek and come to Him through His Son, He makes our ‘yoke’ lighter. Our trials don’t end, but they become easier to bear, because we have a very strong Mediator to The Father for us. And didn’t our Father create everything? How would any father treat his children whom he loves so much?

We all are here in this flesh to make ‘choice’ as to whom we will serve. If not The Father through His Son Jesus Christ, then the ‘default’ is to Satan. There’s no middle-ground. To fear ‘flesh’ death is to be weak in God’s work. If we have ‘any’ fear, it should be of GOD, Who has Power to destroy ‘both’, flesh and soul, forever. Did our Lord mean all this as a ‘threat’ then? No… He meant it to those to whom it is given to. Not all are ‘able’ to bear a cross even ‘similar’ to His. But His chosen will have a similar ‘cross’ to bear, and He will make them prepared for it when the time comes, for they are His ‘chosen’ vessels. God’s Word is full of examples of this type, such as Paul especially:

2 Cor 11:23-31
23    Are they ministers of Christ? (I speak as a fool) I am more; in labours more abundant, in stripes above measure, in prisons more frequent, in deaths oft.
24    Of the Jews five times received I forty stripes save one.
25    Thrice was I beaten with rods, once was I stoned, thrice I suffered shipwreck, a night and a day I have been in the deep; 26    In journeyings often, in perils of waters, in perils of robbers, in perils by mine own countrymen, in perils by the heathen, in perils in the city, in perils in the wilderness, in perils in the sea, in perils among false brethren; 27    In weariness and painfulness, in watchings often, in hunger and thirst, in fastings often, in cold and nakedness.
28    Beside those things that are without, that which cometh upon me daily, the care of all the churches.
29    Who is weak, and I am not weak? who is offended, and I burn not?
30    If I must needs glory, I will glory of the things which concern mine infirmities.
31    The God and Father of our Lord Jesus Christ, Which is blessed for evermore, knoweth that I lie not.
(KJV)

     Let me take inventory now, comparing my life in Christ with Paul…. Let’s see… can’t remember the last time I had to run for my life for preaching Christ; don’t remember ever receiving stripes on my back from a whip, nor being in prison; I’ve never been stoned; I did have a type of ‘shipwreck’ on a fishing boat once though I didn’t spend “a night and a day” in the sea; can’t say I’ve really ever ‘hungered’ or ‘thirsted’ like Paul… get the idea?
     Clearly, compared to what some have suffered, and others must suffer, to be in Christ, how bad do most of us have it? Paul never had a color TV, stereo, automobile, nice house, etc. One thing he did have… was a Mission for Christ Jesus. And was he slack in it? No way. There’s ‘our’ model for following Christ when things get a little rough in our lives. We are to stand up like a child of God and say, “can do”! And all these things Paul experienced, it was because he was preaching The Gospel of Christ. That’s the only Matter he was being persecuted for. So when we suffer persecution for Christ’s sake, because we ‘know’ we are doing His work as servants, then it means we are ticking the ‘wicked one’ off, because we’re wining in the spiritual war against him. One who does more for our Lord must ‘expect’ that kind of attacking in this world of flesh, for Satan has been given power to rule over the flesh world (Luke 4).[Important: Never argue with Satan. Even Michael the Archangel knew this; Jude 1:9]
     Note that God always protected Paul until his Mission was fulfilled. Just like Jonah, a ‘chosen’ one will not get out of their ‘duty’ God has ordained for them. He really makes them ‘tow the line’.
     For most of us in Christ today, who may be ‘called’, but not ‘chosen’, we have a similar responsibility to our Lord. If not, then why would He have ‘called’ us? And further, what is a true servant to Christ? Is it one who believes, but just wants to do whatever they wish to do in life, having an easy existence, and not doing any work for Him? Based on how Paul served our Lord, obviously not. And that’s what many believers truly want, an ‘easy way out’, meaning not suffering any persecution for making a ‘stand’ for Christ. The Gospel Armour of Ephesians 6 fits real well here.

John 17:13-18
13    And now come I to thee; and these things I speak in the world, that they might have My joy fulfilled in themselves.
14    I have given them Thy word; and the world hath hated them, because they are not of the world, even as I am not of the world.
15    I pray not that Thou shouldest take them out of the world, but that Thou shouldest keep them from the evil.
16    They are not of the world, even as I am not of the world.
17    Sanctify them through Thy truth: Thy word is truth.
18    As Thou hast sent Me into the world, even so have I also sent them into the world.
(KJV)

     Those who are ‘called’ and ‘chosen’ are sent into the world for Christ’s sake. Notice above Christ prayed to The Father that His servants not be taken out, but stay in the ‘field’ doing His work. How is it that so many wish to leave it without fulfilling their God given Mission, just to escape persecution, especially when the ‘times’ are getting so exciting? It’s time to ‘stand up’, and make a difference in the world, for our Lord Christ Jesus, being His servants.