Your definition you are in Christ, a Christian or you are in church,
This bit
1Co_6:16 What? know ye not that he which is joined to an harlot is one body? for two, saith he, shall be one flesh.
1Co_6:17 But he that is joined unto the Lord is one spirit.
If you put a man in a JW church he will be come a JW, be impossible to be come anything else,
Put a man in teh catholic church he will become a catholic, no way will he become a morman, because its teh catholic doctrines and traditions he will serve.
Put a man in the SDA church he will become a SDA for that is what he is joined to, its doctrines , tradition he will serve.
Now take a man and let Him go to Christ, and He will become a Christian, and Christ will do what He does best, change that man into His own image, for that is what a Christians is supposed to be.
Take a stick put it into a red tin of paint it wont become blue, is it so hard to understand.
Mar 7:6 He answered and said unto them, Well hath Esaias prophesied of you hypocrites, as it is written, This people honoureth me with their lips, but their heart is far from me.
Mar 7:7 Howbeit in vain do they worship me, teaching for doctrines the commandments of men.
Mar 7:8 For laying aside the commandment of God, ye hold the tradition of men, as the washing of pots and cups: and many other such like things ye do
and so it will be untill all eyes see,