watch out the deceivers, even those who claim to be Christian

"For such people are false apostles, deceitful workers, disguising themselves as apostles of Christ. And no wonder, for even Satan disguises himself as an angel of light. So it is no surprise if his servants, also, disguise themselves as servants of righteousness. Their end will correspond to their deeds." 2 Corinthians 11

"They went out from us, but they did not really belong to us. For if they had belonged to us, they would have remained with us; but their going showed that none of them belonged to us." 1 John 2:19