Matthew 7:15
"Look out for deceiving prophets, who approach you wearing sheep's clothing, but who are [actually] starving wolves in their hearts.
Matthew 15:5-14
But you say, 'Whoever says to his father or mother, I have given to God the money I could have helped you with;'
Mark 13:14
"But when you see that disgusting thing that causes total destruction [i.e., the Roman army. See Luke 21:20] standing where it ought not to be [i.e., surrounding the besieged city of Jerusalem], (let the reader understand [what is meant by this]), then those of you in Judea are to run away into the [nearby] mountains.
Mark 13:22-23
For false Christs and false prophets will appear and they will perform [miraculous] signs and [supernatural] wonders in order to lead astray [even] the elect, if possible.
Acts 20:30
[Indeed, even] from among your own selves [i.e., the body of elders there in Ephesus] some men will arise and, by speaking false things, they will lead away the disciples, [influencing them] to follow them.
2 Corinthians 11:13-15
For such men are false apostles; they are deceitful workers, who disguise themselves as [true] apostles of Christ.
Ephesians 4:13-14
[This is to be done] until we all [eventually] arrive at unity of the faith and full knowledge of the Son of God; at complete [spiritual] maturity; at the [full] height of Christ's [spiritual] stature.
2 Thessalonians 2:8-10
And then the lawless person [See verse 3] will be revealed, the one whom the Lord Jesus will destroy with the breath of His mouth and bring to an end by the brilliant appearance of His presence [i.e., at His second coming].
1 Timothy 4:1-3
Now the Holy Spirit specifically says that in later times [Note: "Later times" in the New Testament usually refers to the period following the first coming of Christ and the establishment of the church], some people will fall away from the faith [i.e., the true teaching of Christianity]. They will pay attention to deceitful spirits [i.e., lying people] and the teaching of evil spirits.
2 Peter 2:1-3
But just as there were false prophets among the people before, there will also be false teachers among you [Christians]. They will privately teach harmful doctrines that destroy people [spiritually], by even denying [that Jesus is] the Master, [and thereby] destroying themselves quickly.
2 Peter 3:16-18
He spoke about these things in all of his letters, which contain some parts that are difficult to understand. [Because of this], ignorant and unstable people twist [his writings], just as they also do to the other Scriptures, to their own destruction.
1 John 2:21
I did not write to you people because you are ignorant of the truth [about these matters], but because you do know it, and because nothing false belongs to the true teaching.
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.