Grace is not a license to keep sinning and confessing. Many false teachers subtly imply that it is such a license and we are warned of this in the Bible.
Jud 1:3 Beloved, when I gave all diligence to write unto you of the common salvation, it was needful for me to write unto you, and exhort you that ye should earnestly contend for the faith which was once delivered unto the saints.
Jud 1:4 For there are certain men crept in unawares, who were before of old ordained to this condemnation, ungodly men,
turning the grace of our God into lasciviousness, and denying the only Lord God, and our Lord Jesus Christ.
The context of 1Joh 1:7-10 is of a once and for all cleansing of ALL sin and ALL unrighteousness whereby we "keep the commandments and walk as He walked (1Joh 2:3-6).
People will snip 1Joh 1:9 from its context and use to teach the sin/repent/sin/repent/sin/repent/sin/repent cycle that many believe.
Carefully read the passage...
1Jn 1:7 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 cleanseth us from all sin.
1Jn 1:8 If we say that we have no sin, we deceive ourselves, and the truth is not in us.
1Jn 1:9 If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
1Jn 1:10 If we say that we have not sinned, we make him a liar, and his word is not in us.
Now compare it to the cleansing mentioned here...
Heb 10:19 Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus,
Heb 10:20 By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh;
Heb 10:21 And having an high priest over the house of God;
Heb 10:22 Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water.
Heb 10:23 Let us hold fast the profession of our faith without wavering; (for he is faithful that promised
Heb 10:24 And let us consider one another to provoke unto love and to good works:
Heb 10:25 Not forsaking the assembling of ourselves together, as the manner of some is; but exhorting one another: and so much the more, as ye see the day approaching.
Heb 10:26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
Heb 10:27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
Heb 10:28 He that despised Moses' law died without mercy under two or three witnesses:
Heb 10:29 Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?
To willfully sin after having been cleansed is to despise the Spirit of grace. We are warned against doing that. This is why we are not to pray for someone who sins unto death. Sinning unto death is an act of rebelliohey n for it is the willful turning from the light. God will not work with someone who does that, that person needs to repent and yield to God. There is no forgiveness in rebellion. There is only no condemnation for those who are IN Christ Jesus whom walk after the Spirit (Rom 8:1).
Many people want to believe in a forgiveness IN sin. If one is abiding in Jesus then one cannot possibly be sinning because Jesus does not lead us to sin. We have to forsake Christ in turning away from Him in order to sin and that is what the condemnation is, ie. a rejection of light.