Sin is breaking God's Ten Commandment law. The Bible says that when we knowingly break any command of God, we are sinning as transgression of the law of God (1 John 3:4) and rebellion against God (James 4:17).Romans 5:12 shows us the consequences of what Adam and Eve started, that, "just as through one man sin entered the world, and death through sin," death has "spread to all men, because all sinned." One sin is as bad as another sin, in the eyes of God.
eg..Luk 16:10 He that is faithful in that which is least is faithful also in much: and he that is unjust in the least is unjust also in much.
Jas 2:10 For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all.
Bible says that those who sin do not have eternal life:1Jn 3:15 Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him.
Whosoever is born of God will not commit sin. And saints are made free from sin to become the servants of righteousness. The word of God, prayers keeps away from sins and also we need to keep as far away as possible from sinful places and sinful people who corrupt good morals.
1 John 3:9 whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God.
1 John 5:18 We know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not.
Sin brings separation (spiritual death) from God:
eg..Gen 2:17 But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
Gen 3:2, 3 And the woman said unto the serpent, We may eat of the fruit of the trees of the garden: But of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die.
Joh 8:51 Verily, verily, I say unto you, If a man keep my saying, he shall never see death.
The Bible says that Sin should always be confessed , mourned over, hated, departed from, avoided even in appearance from all forms,shoulded be guarded, to be prayed to keep away and delivered from sins, to ask God to cleanse our sins with the Precious Blood of Jesus Christ. Christ not only pardons repentant sinners, but He restores in them the image of God.