As posted in the first post to you brother, JESUS has made provision for all sin, past, present and future through His sacrifice and death on the cross on our behalf.
1 JOHN 1:7 does not contradict or cancel out 1 JOHN 1:9 it is in harmony with it.
Let's look at the complete context..
1 JOHN 1:5-10
[5], This then is the message which we have heard of him, and declare to you, that
God is light, and in him is no darkness at all.
[6],
If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:
[7],
But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleans us from all sin.
Scripture here is saying that if we walk in the truth of God's Word then we have fellowship with JESUS and one another as God's children. It we BELIEVE and FOLLOW what God's Word says v7 the blood of JESUS Christ his son CLEANSES US from ALL SIN.
[8], If we say that we have no sin, we deceive ourselves, and the truth is not in us.
We do not become sinless when we become born again we are forgiven of past sins *ROMANS 3:25. Now we are to grow in God's GRACE as new borns and NEW Christian believers. There are two categories of sin according to God's Word. 1 KNOWN SIN the sins that we know about that are sin and 2 UNKNOWN sin those things that may be in our lives that we no not as yet know are sin because we do not have the knowledge of what that sin maybe. *JAMES 4:17. When God gives us a knowledge when of the truth or what may be sin he expects us to REPENT and BELIEVE His WORD and FOLLOW it *ACTS 17:30-31. There fore as the scripture says; IN TIMES OF IGNORANCE (when we do not have a knowledge of the truth) God winks at (we are not accountable) BUT when a KNOWLEDGE of the truth has been given us, God calls all men everywhere to REPENT *ACTS 17:30-31.
REPENTANCE and CONFESSION of PRESENT and FUTURE SINS is a part of Sanctification. This is a work of a lifetime. It we continue in KNOWN UNREPENTANT sin then we are still in our sins and are not in a saved state before God because we reject the gift of God's dear son *ROMANS 6:23; HEBREWS 10:26-27.
[9], If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
This is the CONDITION of receiving God's FORGIVENESS; Past; present and future and agrees with v7 that states the BLOOD of JESUS CHRIST His Son CLEANSES US FROM ALL UNRIGHTEOUSNESS. Note here brother that FORGIVENESS (past, present and future) is condtional on REPENTANCE and CONFESSION when SIN happens.
[10], If we say that we have not sinned, we make him a liar, and his word is not in us.
Note have sinned is talking about past sins committed in the "present tense" This means the application is that every time we have sinned (always past) then we are to REPENT AND CONFESS of these sins. The application is thoughout our life (Sanctification).
............
According to God's Word the difference between the children of God and the children of the devil is that the children of God do not practice KNOWN sin or sins that they KNOW are sin. The children of God have their sins forgiven and have been cleansed from their sins through repentance and confession of sin and Faith in God's Word *1 JOHN 1:9.
The reason we need to be Born again is because we sin and cannot stop sinning. Those who are born of God and are God's children do not practice sin. The blood of JESUS Chrsit does indeed cleanse us from all sin as 1 JOHN 1:7 says as Christs sacrifice for sin has made provision for all sin. However, this provision based on REPENTANCE, CONFESSION and FAITH.
ROMANS 3:25
Whom God has set forth to be a propitiation through faith in his blood, to declare his righteousness FOR THE REMISSION OF SINS
THAT ARE PAST, through the forbearance of God.
1 JOHN 3:3-10
[3], And
every man that has this hope in him purifies himself, even as he is pure.
[4], Whoever commits sin transgresses also the law: for
sin is the transgression of the law.
[5], And you know that he was manifested to take away our sins; and in him is no sin.
[6],
Whoever abides in him sins not:
whoever sins has not seen him, neither known him.
[7], Little children, let no man deceive you: he that does righteousness is righteous, even as he is righteous.
[8],
He that commits sin is of the devil; for the devil sins from the beginning. For this purpose, the Son of God was manifested, that he might destroy the works of the devil.
[9],
Whoever is born of God does not commit sin; for his seed remains in him: and he cannot sin, because he is born of God.
[10],
In this the children of God are manifest, and the children of the devil: whoever does not righteousness is not of God,
neither he that loves not his brother.
1 JOHN 2:3-4
[3], And
hereby we do know that we know him, if we keep his commandments.
[4],
He that said, I know him, and keeps not his commandments, is a liar, and the truth is not in him.
Context..
1 JOHN 2:1
[1], My little children,
these things write I to you, that you sin not. And
if any man sin, we have an advocate with the Father, Jesus Christ the righteous.
According to God's Word FORGIVENESS of sin (past, present and future) is conditional on REPENTANCE and CONFESSION of sin after sin happens. All those who continue in known unrepentant sin without REPENTANCE AND CONFESSION will not enter the kingdom of Heaven because they reject the gift of God's dear son *ROMANS 6:23.
God bless