II Timothy 2:19
Nevertheless, the firm foundation of God stands, having this seal, The Lord knows those who are His, and, Everyone who names the name of the Lord is to abstain from wickedness.

I John 1:8
If we say that we have no sin, we are deceiving ourselves and the truth is not in us.

Ecclesiastes 7:20
Indeed, there is not a righteous man on earth who continually does good and who never sins.

I John 1:10
If we say that we have not sinned, we make Him a liar and His word is not in us.

I John 5:13
These things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life. (I John is written to Christians)

I John 5:16-17
16 If anyone sees his brother committing a sin not leading to death, he shall ask and God will for him give life to those who commit sin not leading to death. There is a sin leading to death; I do not say that he should make request for this. 17 All unrighteousness is sin, and there is a sin not leading to death.

Sin Unto Death:

Matthew 12:22-32
22 Then a demon-possessed man who was blind and mute was brought to Jesus, and He healed him, so that the mute man spoke and saw. 23 All the crowds were amazed, and were saying, "This man cannot be the Son of David, can he?" 24 But when the Pharisees heard this, they said, "This man casts out demons only by Beelzebul the ruler of the demons." 25 And knowing their thoughts Jesus said to them, "Any kingdom divided against itself is laid waste; and any city or house divided against itself will not stand. 26 If Satan casts out Satan, he is divided against himself; how then will his kingdom stand? 27 If I by Beelzebul cast out demons, by whom do your sons cast them out? For this reason they will be your judges. 28 But if I cast out demons by the Spirit of God, then the kingdom of God has come upon you. 29 Or how can anyone enter the strong man's house and carry off his property, unless he first binds the strong man? And then he will plunder his house. 30 He who is not with Me is against Me; and he who does not gather with Me scatters. 31 Therefore I say to you, any sin and blasphemy shall be forgiven people, but blasphemy against the Spirit shall not be forgiven. 32 Whoever speaks a word against the Son of Man, it shall be forgiven him; but whoever speaks against the Holy Spirit, it shall not be forgiven him, either in this age or in the age to come.

Pharisees trying to catch Jesus in his own words (they were hypocrites)

Mark 12:13-17
13 And they sent some of the Pharisees and Herodians to Him, in order to trap Him in a statement. 14 And they came and said to Him, "Teacher, we know that You are truthful, and defer to no one; for You are not partial to any, but teach the way of God in truth. Is it lawful to pay a poll-tax to Caesar, or not? 15 "Shall we pay, or shall we not pay?" But He, knowing their hypocrisy, said to them, "Why are you testing Me? Bring Me a denarius to look at." 16 And they brought one. And He said to them, "Whose likeness and inscription is this?" And they said to Him, "Caesar's." 17 And Jesus said to them, "Render to Caesar the things that are Caesar's, and to God the things that are God's." And they were amazed at Him.

We can be forgiven though:

I John 1:9
If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness.

I John 1:7
but if we walk in the Light as He Himself is in the Light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin.

Psalm 119:105
Your word is a lamp to my feet And a light to my path.

We can't live in sinless perfection though:

I Timothy 6:12
Fight the good fight of faith; take hold of the eternal life to which you were called, and you made the good confession in the presence of many witnesses.

Ephesians 6:11-12
11 Put on the full armor of God, so that you will be able to stand firm against the schemes of the devil. 12 For our struggle is not against flesh and blood, but against the rulers, against the powers, against the world forces of this darkness, against the spiritual forces of wickedness in the heavenly places.

II Corinthians 10:3-5
3 For though we walk in the flesh, we do not war according to the flesh, 4 for the weapons of our warfare are not of the flesh, but divinely powerful for the destruction of fortresses. 5 We are destroying speculations and every lofty thing raised up against the knowledge of God, and we are taking every thought captive to the obedience of Christ,

Hebrews 11:6
And without faith it is impossible to please Him, for he who comes to God must believe that He is and that He is a rewarder of those who seek Him.

God doesn't tempt us into sin:

James 1:13
Let no one say when he is tempted, I am being tempted by God"; for God cannot be tempted by evil, and He Himself does not tempt anyone.

The Word of God Leads us to Repent:

Acts 17:30
Therefore having overlooked the times of ignorance, God is now declaring to men that all people everywhere should repent,

II Peter 3:9
The Lord is not slow about His promise, as some count slowness, but is patient toward you, not wishing for any to perish but for all to come to repentance.

Romans 8:1
THEREFORE there is now no condemnation for those who are in Christ Jesus.

The Apostles' struggle with sin:

Romans 7:14-25
14 For we know that the Law is spiritual, but I am of flesh, sold into bondage to sin. 15 For what I am doing, I do not understand; for I am not practicing what I would like to do, but I am doing the very thing I hate. 16 But if I do the very thing I do not want to do, I agree with the Law, confessing that the Law is good. 17 So now, no longer am I the one doing it, but sin which dwells in me. 18 For I know that nothing good dwells in me, that is, in my flesh; for the willing is present in me, but the doing of the good is not. 19 For the good that I want, I do not do, but I practice the very evil that I do not want. 20 But if I am doing the very thing I do not want, I am no longer the one doing it, but sin which dwells in me. 21 I find then the principle that evil is present in me, the one who wants to do good. 22 For I joyfully concur with the law of God in the inner man, 23 but I see a different law in the members of my body, waging war against the law of my mind and making me a prisoner of the law of sin which is in my members. 24 Wretched man that I am! Who will set me free from the body of this death? 25 Thanks be to God through Jesus Christ our Lord! So then, on the one hand I myself with my mind am serving the law of God, but on the other, with my flesh the law of sin.