Ephesians 4:20-24
But you people did not learn Christ that way [i.e., the above described life is not compatible with a commitment to Christ].
1 Thessalonians 2:13
And because of this we also thank God continually that, when you people received the message of God, which you heard from us, you did not accept it as a message from [mere] human beings, but as it truly is, the message from God, which is at work in you believers.
1 John 2:19
These antichrists left our group [i.e., withdrew their fellowship from us], but they were not [really a part] of us, for if they had been, they would have continued [to participate] with us. But, by their leaving us, it proved that none of them were [really] a part of our group [after all].
1 John 2:27
And this is important to you: The "special gift," which you received from God [See verse 20], continues to live in your hearts, [so that] you do not need anyone to teach you [anything different]. But, since this same "special gift" teaches you concerning everything that is true, and [what it teaches] is not false, you should continue to live in [fellowship with] Christ.