Many Christians spend a great deal of time remembering their sins of the past.  They live in guilt and condemnation for the things they have done and believe that enumerating their faults before God will bring them salvation.  The apostle Paul had a past filled with evil deeds done toward believers.  With great zeal he persecuted the church.

Acts 26:9-11
     I verily thought with myself, that I ought to do many things contrary to the name of Jesus of Nazareth.
     Which thing I also did in Jerusalem: and many of the saints did I shut up in prison, having received authority from the chief priests; and when they were put to death, I gave my voice against them.
     And I punished them oft in every synagogue, and compelled them to blaspheme; and being exceedingly mad against them, I persecuted them even unto strange cities.

Although Paul had this past he did not focus his life on guilt and condemnation over the thoughts and deeds of the past.  Forgetting those things which are behind.

Romans 8:1
     There is therefore now no condemnation to them which are in Christ Jesus,

You do not receive salvation by confessing and remembering your sins.  You receive salvation by confessing and remembering the savior from sins, the Lord Jesus Christ.

Romans 10:9
     That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.

Romans 3:23-25
     For all have sinned, and come short of the glory of God;
     Being justified [just as if I never sinned!] freely by his grace through the redemption that is in Christ Jesus:
     Whom God hath set forth to be a propitiation [payment] through faith [believing] in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;

Acts 10:43
     To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins.

When we confessed Jesus Christ as our Lord and believed that God raised him from the dead we received remission of sins that are past.  We do not remember and enumerate our sins.  We remember and confess the Lord Jesus Christ and God declares us justified.  It is just as if we never sinned.  Therefore, we are to forget the sin consciousness, guilt, and condemnation over things thought and done in the past and remember the kindness, mercy, forgiveness, and love of God.

Isaiah 43:25
     I, even I, am he that blotteth out thy transgressions for mine own sake, and will not remember thy sins.

Hebrews 8:12
     For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more.

If God does not remember our sins and iniquities why do we want to keep thinking about them?  When sins that God has forgiven and forgotten are brought up again it cannot be God that reminds you, for God, once He has forgiven you, has forgotten your sins.

Isaiah 38:17
     Behold, for peace I had great bitterness: but thou hast in love to my soul delivered it from the pit of corruption: for thou hast cast all my sins behind thy back.

God uses figures of speech in His Word to emphasize that which is most important.  God is a spirit and as such has no back.  The emphasis is that God has but our sins behind Him where He cannot see them.  He has forgotten them.  He has put the past in the past.  We too should forget the sins that are past and remember the love He has toward us.

Psalm 103:12
     As far as the east is from the west, so far hath he removed our transgressions from us.

The east and west never meet.  If you go north and reach the north pole you begin to go south.  But if you go east you never reach the west.  You just keep going east.  God has removed our sins and transgressions that far from us.  Why would you ever want to remember them?

Isaiah 40:2
     Speak ye comfortably to Jerusalem, and cry unto her, that her warfare is accomplished, that her iniquity is pardoned: for she hath received of the Lord's hand double for all her sins.

In the Bible lands and times a person's debts were posted at the gate of the city where all could see his faults.  When the debt was paid the elders of the gate would fold the posted debt double to show that the debt was paid.  It was no longer visible.  Our sins are forgiven, our iniquity is pardoned; God doubles the record so that the sins are no longer visible and we are white as snow.  God casts our sins behind His back.  He removes our transgressions as far as the east is from the west. He remembers them no more.  What a great and wonderful God.

Ephesians 2:11-13
     Wherefore remember, that ye being in time past Gentiles in the flesh, who are called Uncircumcision by that which is called the Circumcision in the flesh made by hands;
     That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:
     But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.

I Peter 2:10
     Which in time past were not a people, but are now the people of God: which had not obtained mercy, but now have obtained mercy.

Ephesians 2:2-5
     Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience:
     Among whom also we all had our conversation [way of life] in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind, and were by nature the children of wrath, even as others.
     But God, who is rich in mercy, for his great love wherewith he loved us,
     Even when we were dead in sins, hath quickened us [made us alive] together with Christ, (by grace ye are saved;)
 
What are we to remember about the past?  We are to remember the state that we were in: dead in trespasses and sins, without God and without hope, aliens, strangers, children of wrath and disobedience.  AND we are to remember the great mercy, grace and love of God who made us alive, raised us up, and seated us at His own right hand together with Christ Jesus.  God who made us His sons and gave us eternal life.  We are not to be filled with sin consciousness, guilt and condemnation.  Rather we are to be filled with thankfulness and love for our wonderful God who delivered us by His mercy, love, and grace.  We are to remember the benefits of God.

Psalm 103:2-5
     Bless the Lord, O my soul, and forget not all his benefits:
     Who forgiveth all thine iniquities; who healeth all thy diseases;
     Who redeemeth thy life from destruction; who crowneth thee with lovingkindness and tender mercies;
     Who satisfieth thy mouth with good things; so that thy youth is renewed like the eagle's