Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness. You know that he appeared in order to take away sins, and in him there is no sin. No one who abides in him keeps on sinning; no one who keeps on sinning has either seen him or known him. Little children, let no one deceive you. Whoever practices righteousness is righteous, as he is righteous. Whoever makes a practice of sinning is of the devil, for the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the works of the devil. No one born of God makes a practice of sinning, for God's seed abides in him, and he cannot keep on sinning because he has been born of God. By this it is evident who are the children of God, and who are the children of the devil: whoever does not practice righteousness is not of God, nor is the one who does not love his brother. (1 John 3:4-10)
John was writing to the early church as many did not show fruits of repentance. There are many people who go to church or call themselves Christians but they truly are not born again. We really can't help but to sin. It is our nature. But Christ nailed our nature to the cross defeating sins hold over us. When we recognize this fact, our eyes are open to our sinfulness. We see what God hates and desire a new life in His Son! Empowered by the Holy Spirit, we begin a new life growing in God's love. This is a life long process. When we fall down, God will pick us up. But we must understand that if there is no change in our life or no desire to change because we don't hate the former things we did, then we are not truly born again!
For if we go on sinning deliberately after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a fearful expectation of judgment, and a fury of fire that will consume the adversaries. Anyone who has set aside the law of Moses dies without mercy on the evidence of two or three witnesses. How much worse punishment, do you think, will be deserved by the one who has trampled underfoot the Son of God, and has profaned the blood of the covenant by which he was sanctified, and has outraged the Spirit of grace? For we know him who said, “Vengeance is mine; I will repay.” And again, “The Lord will judge his people.” It is a fearful thing to fall into the hands of the living God.
But recall the former days when, after you were enlightened, you endured a hard struggle with sufferings, sometimes being publicly exposed to reproach and affliction, and sometimes being partners with those so treated. For you had compassion on those in prison, and you joyfully accepted the plundering of your property, since you knew that you yourselves had a better possession and an abiding one. a great reward. For you have need of endurance, so that when you have done the will of God you may receive what is promised.
For, “Yet a little while,
and the coming one will come and will not delay;
but my righteous one shall live by faith,
and if he shrinks back,
my soul has no pleasure in him.”