Christians are supposed to make every effort to resist sin. This is one of the major themes of the entire Bible.
In walking the path Christ assigned to us, he gave us rules to follow. In walking that path, we have faith that the instructions he gave us are accurate. One of those broad instructions is don’t sin.
If you sin then you’re not following Christ, at least temporarily. Therefore, sin is apostasy from the faith as 2 Peter 2:20-22 shows.
The author of Hebrews said in 12:4, "In your struggle against sin, you have not yet resisted to the point of shedding your blood." So sin is something to be struggled against and, if necessary, resisted to the point of shedding your own blood. Resistance to sin is more important than your own blood, then, because obeying God is more important than not obeying God, which is what sin is... willful or unwilful disobedience.
I don't believe we are ever going to attain sinless perfection on Earth, but what we can attain is a lifelong struggle and resistance to sin. There will be victories and defeats. As evidenced by those babes in Christ who were still worldly, jealous, and quarreling spiritual maturity is not instantaneous per 1 Corinthians 3:1-3.
1. We access God's grace through faith per Romans 5:1,2
2. Sinning is apostasy which is a departure from the faith per 2 Peter 2:20-22
3. We should struggle to resist sin per Hebrews 12:4
4. To those who by persistence in doing good seek glory, honor and immortality, he will give eternal life. Per Romans 2:7
5. If you sin knowingly or unknowingly, you can confess your sin to God in Jesus name, receive forgiveness, then continue your walk in the light (struggling against and resisting sin) per 1 John 1:5-10
6. For those who continue is unrepentant sin, a walk in darkness, nothing remains for that person but a fearful expectation of judgment and of raging fire that will consume the enemies of God per Hebrews 10:26,27