Jude 1:4

2 Peter 2:1-3 NIV
But there were also false prophets among the people, just as there will be false teachers among you. They will secretly introduce destructive heresies, even denying the sovereign Lord who bought them —bringing swift destruction on themselves. Many will follow their depraved conduct and will bring the way of truth into disrepute. In their greed these teachers will exploit you with fabricated stories. Their condemnation has long been hanging over them, and their destruction has not been sleeping.

2 Peter 2:10 NIV
This is especially true of those who follow the corrupt desire of the flesh and despise authority. Bold and arrogant, they are not afraid to heap abuse on celestial beings;

Galatians 2:4 NIV
This matter arose because some false believers had infiltrated our ranks to spy on the freedom we have in Christ Jesus and to make us slaves.