ANSWER: Although all humans are sinners before the eyes of God (Romans 3:23), he has, in love, given his only Son in order to reconcile us to him. We have all lost our lives to Satan and believed his subtle lies, which is why Jesus had to come and literally buy us back or redeem us from him (Galatians 3:13). The only difference between sinners is that those who believe in God and have become true Christians are in a state of grace and forgiveness. The sacrifice of Christ, when it is fully accepted by a person, makes them a son or daughter of the Eternal.
God does not limit himself concerning how much disobedience he will forgive IF someone, who is a sinner, is willing to repent. In fact, Jesus stated to Peter that we should forgive others as many times as is needed (Matthew 18:22)! In Matthew 12 he taught that EVERY sin and blasphemy will be forgiven by God (Matthew 12:31 - 32). The only exception he made is when a person willfully wishes to be a sinner. This type of disobedience in not forgiven because a person WILLFULLY (and not out of weakness or deception which we can all fall prey to) REFUSES to respond to his love and repent!
Our heavenly Father wants to save everyone (1Timothy 2:4) and therefore is quick to forgive sinners. The only question is how much pain we are willing to go through before we decide to believe him and not the devil. In Hebrews 12 Paul says God, as a loving Father, corrects every person He works with and considers one of his spiritual children (Hebrews 12:5 - 6).
Satan's will is to have you think how bad you are and to believe the Eternal does not love you. No matter how much a sinner you are God ALWAYS loves you and will allow you to go through as much suffering as necessary so that you finally believe Him and not His adversary. He wants us to repent (Acts 2:38), which means to change our mind from seeking the will of the devil (e.g. which is to NOT forgive yourself after you have been forgiven) to His will.
Jesus, in his Sermon on the Mount, stated that if we ask the Father for something (according to His perfect love and will) it will be given to us (Matthew 7:7 - 8). It is God's will that we ask for forgiveness. Although He knows we are weak and sometimes give in to the temptations and deceptions of sin, He promises to ALWAYS forgive is we ask. He also promises to remove, ultimately, all traces of rebellion within us (1John 1:9).
When you pray, ask Him to help you believe Him and accept His forgiveness no matter how bad you think is the sin you have committed. Belief (faith) in God can lead any sinner to true repentance and reconciliation.