Both the Old and New Testaments have much to say about sin, but what is sin? Sin is disobedience to God, any action, thought or word that is unpleasing to Him. Everyone sins (Romans 3:23), and because of their sinning they cut themselves off from God (Revelation 21:27). All sin is to God (Psalm 51:4), for when we sin, perhaps in anger to a fellow human being, we are not treating him as God would have us do. God tells us to love and respect people (1 Peter 2:17; Mark 12:31), and above all to love Him (Deuteronomy 6:5; 30:16; Matthew 22:37, 38; Mark 12:29-31).

As we know from the Genesis 3:1-24 account of Adam and Eve, both of them sinned, and Adam as the federal representative of mankind tarred the whole human race with sin; therefore everyone is born a sinner (Romans 3:23). In our sinful state none of us respects God. In this condition, because of our disobedience and rebellion against Him we stand before Him without hope of a reprieve from death, which we deserve – both physical and spiritual.

But there is a Way (John 14:6) out from this situation. The Way out is a Person – the Person of Jesus Christ, the Son of God. He died in our place on a cross; thereby He became our substitute so that God can impute His sinless life and death to our account. There is but one requirement for this to happen, we must have faith and trust in Jesus. However, this is a God-given gift (Ephesians 2:8, 9); for when we are spiritually dead because of our sin, we cannot stretch out our hands to receive life. It’s a bit like Lazarus who was dead in the tomb (John 11:40-44). Only Jesus could give him life. He couldn’t ask Jesus to restore his life. The same applies to all who are dead in their sin. We can seek the Lord, as indeed the Scriptures say we can (Acts 15:17), but only He can give life through His Spirit. Jesus said He is the Resurrection and the Life (John 11:25). No one comes to the Father except through Him. (John 14:6)

Jesus further explained that one must be “born of water and the Spirit”  to see the kingdom of God. (John 3:3) He said, “That which is born of flesh is flesh, and that which is born of the Spirit is spirit,” and, “You must be born again.” (vs 6, 7)

That is not the end of the matter, because meanwhile, before our mortal bodies die and while we live here on earth, ‘the prince of the power of the air’ ‘works in the sons of disobedience’ (Ephesians 2:2). Christ overcame him at the cross by being resurrected from the dead, but He left him here until the day of reckoning, i.e., the Day of the Lord (Joel 2:31; Acts 2:20), when Jesus will return to earth to judge all (Revelation 20:11-15). He will separate the sheep from the goats. (Matthew 25:31-46)

Satan knows he will have to face judgment (Revelation 20:10), and therefore he takes every opportunity to attack and weaken the saints. He will try to make them feel inadequate and guilty. So the saints are in conflict with him. They have to be alert to his wiles (1 Peter 5:8, 9), and they must look to the Holy Spirit for help in overcoming temptation. He is their Helper (John 14:16).

All the saints are justified by the vicarious death of Jesus, and they are declared ‘saints’, which simply means believers, but their behaviour often falls short of holy living. God has said, “You shall be holy, for I the LORD your God am holy.” (Leviticus 19:2; 20:7, 8; 1 Peter 1:16) And Peter the Apostle went on to write, ‘And if you call on the Father, who without partiality judges according to each one’s work, conduct yourselves throughout the time of your stay here in fear; knowing you were not redeemed with corruptible things, like silver or gold, from your aimless conduct received by tradition from your fathers, but with the precious blood of Christ, as of a lamb without blemish and without spot.’

That clearly points us to our responsibility to live holy lives, which means living to the glory of God,* alway vigilant for overcoming sin on a daily basis. We seek the aid of the Spirit and look to God’s Word, the Bible for our guidance (Psalm 119:11).

*  https://thebiblicalway.blog/2018/01/05/do-all-to-the-glory-of-god/