Jude 1:4

For there crept in stealthily certain men, who of old were set forth for this condemnation, ungodly men, changing the grace of our God into lasciviousness; and denying the only Master and our Lord Jesus Christ.

Galatians 2:4

and that was because of the false brethren secretly introduced, who, indeed, crept in to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage;

1 Peter 2:8

and "a stone of stumbling, and rock of offense"; who stumble, being disobedient to the word, to which also they were appointed.

1 John 2:22

Who is the liar, but he that denies that Jesus is the Christ? This is the Anti-Christ, he that denies the Father and the Son.

2 Timothy 3:6

For of these are those who creep into houses, and lead captive silly women laden with sins, and led on by manifold desires,

Matthew 13:25

and, while men were sleeping, his enemy came and sowed tares in the midst of the wheat, and went away.

John 17:3

And this is the eternal life, that they know Thee, the only true God, and Jesus Christ Whom Thou didst send.

Acts 11:23

who, having come, and having seen the grace of God, rejoiced, and was exhorting all that, with purpose of heart, they should cleave to the Lord;

Acts 15:24

Forasmuch as we heard that some from among us troubled you with words, unsettling your souls??o whom we gave no directions;

Romans 6:1-2

What, then, shall we say? Shall we persist in sin, that grace may abound?

Romans 9:21-22

Or has not the potter a right over the clay, out of the same lump to make one part a vessel unto honor, and another unto dishonor?

Galatians 5:13

For ye were called to freedom, brethren; only use not your freedom for an occasion to the flesh, but through love serve one another;

Ephesians 4:14

that we may no longer be babes, billow-tossed, and carried about with every wind of teaching, in the sleight of men, in the craftiness suited to the artifice of error;

1 Timothy 6:15-16

which in His own times the Happy and Only Potentate will show, the King of kings and Lord of lords,

Titus 1:15-16

To the pure all things are pure; but to the defiled and unbelieving nothing is pure; but both their mind and their conscience have become defiled.

Titus 2:11-12

For the salvation-imparting grace of God appeared to all men,

Hebrews 12:15-16

looking carefully, lest there be any one falling short of the grace of God; lest any root of bitterness, springing up, trouble you, and through it many be defiled;

1 Peter 2:16

as free, and not holding your freedom as a cloak for wickedness, but as servants of God.

1 Peter 4:18

And, if the righteous, with difficulty, is saved, where shall the ungodly and sinner appear?

2 Peter 2:1-3

But there arose false prophets also among the people, as among you also there will be false teachers, who, indeed, will stealthily bring in destructive heresies, denying even the Master Who bought them, bringing upon themselves swift destruction:

2 Peter 2:5-6

and spared not the old world; but preserved Noah, an eighth person, a preacher of righteousness, bringing a flood upon a world of ungodly people;

2 Peter 2:10

but especially those who walk after the flesh in a desire for pollution, and despise dominion; daring, self-willed, they tremble not, when railing at dignities;

2 Peter 2:18-22

For, uttering great swelling words of vanity, they entice, in desires of the flesh, by their lasciviousness, those just escaping from those who live in error;

2 Peter 3:7

but the present heavens and the earth, by the same word, have been stored up for fire, being kept unto the day of judgment and perdition of ungodly men.

Jude 1:15

to execute judgment upon all, and to convict all the ungodly of all their works of ungodliness, which in ungodliness they committed, and of all the hard things which, as ungodly sinners, they spake against Him."

Revelation 15:4

Who will not fear, O Lord, and glorify Thy name? because Thou only art holy; because all the nations shall come, and worship before Thee; because Thy righteous acts were made manifest."

Treasury of Scripture Knowledge

Summary

For there are certain men crept in unawares, who were before of old ordained to this condemnation, ungodly men, turning the grace of our God into lasciviousness, and denying the only Lord God, and our Lord Jesus Christ.

Bible References

Crept

Matthew 13:25
and, while men were sleeping, his enemy came and sowed tares in the midst of the wheat, and went away.
Acts 15:24
Forasmuch as we heard that some from among us troubled you with words, unsettling your souls??o whom we gave no directions;
Galatians 2:4
and that was because of the false brethren secretly introduced, who, indeed, crept in to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage;
Ephesians 4:14
that we may no longer be babes, billow-tossed, and carried about with every wind of teaching, in the sleight of men, in the craftiness suited to the artifice of error;
2 Timothy 3:6
For of these are those who creep into houses, and lead captive silly women laden with sins, and led on by manifold desires,
2 Peter 2:1
But there arose false prophets also among the people, as among you also there will be false teachers, who, indeed, will stealthily bring in destructive heresies, denying even the Master Who bought them, bringing upon themselves swift destruction:

Who

Romans 9:21
Or has not the potter a right over the clay, out of the same lump to make one part a vessel unto honor, and another unto dishonor?
1 Peter 2:8
and "a stone of stumbling, and rock of offense"; who stumble, being disobedient to the word, to which also they were appointed.
2 Peter 2:3
and, in covetousness, will they, with feigned words, make merchandise of you; for whom the judgment from of old lingers not, and their destruction slumbers not.

Turning

Romans 6:1
What, then, shall we say? Shall we persist in sin, that grace may abound?
Galatians 5:13
For ye were called to freedom, brethren; only use not your freedom for an occasion to the flesh, but through love serve one another;
Titus 2:11
For the salvation-imparting grace of God appeared to all men,
Hebrews 12:15
looking carefully, lest there be any one falling short of the grace of God; lest any root of bitterness, springing up, trouble you, and through it many be defiled;
1 Peter 2:16
as free, and not holding your freedom as a cloak for wickedness, but as servants of God.
2 Peter 2:10
but especially those who walk after the flesh in a desire for pollution, and despise dominion; daring, self-willed, they tremble not, when railing at dignities;

Denying

Titus 1:15
To the pure all things are pure; but to the defiled and unbelieving nothing is pure; but both their mind and their conscience have become defiled.
2 Peter 2:1
But there arose false prophets also among the people, as among you also there will be false teachers, who, indeed, will stealthily bring in destructive heresies, denying even the Master Who bought them, bringing upon themselves swift destruction:
1 John 2:22
Who is the liar, but he that denies that Jesus is the Christ? This is the Anti-Christ, he that denies the Father and the Son.

General references

Matthew 24:11
and many false prophets will arise, and will lead many astray;
1 Timothy 5:15
for already some turned aside after Satan.
James 2:19
You believe that God is one. You do well. The demons also believe, and shudder!