2 Thessalonians 2:15

Now I praise you because you remember me in everything and hold firmly to the traditions, just as I delivered them to you.

Be watchful, stand firm in the faith, act like men, be strong.

that you not be quickly shaken in your mind or be alarmed whether by a spirit or a word or a letter as if from us, to the effect that the day of the Lord has come.

Now we command you, brothers, in the name of our Lord Jesus Christ, that you keep away from every brother who walks in an unruly manner and not according to the tradition which they received from us.

But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons,

holding fast the faithful word which is in accordance with the teaching, so that he will be able both to exhort in sound doctrine and to reprove those who contradict.