Doesn't a believer have to confess every sin to stay saved?

The short answer Settled

No. Confessing restores fellowship with God, not salvation. When a believer sins, he loses close fellowship with God. Confessing the sin brings him back.

Walking with God

John writes so that his readers may share his fellowship: "truly our fellowship is with the Father and with His Son Jesus Christ" (1 John 1:3). Fellowship is sharing life with someone. But "God is light," and "If we say that we have fellowship with Him, and walk in darkness, we lie" (1 John 1:5-6). John says "we," himself included.

Walking in the light does not mean never sinning: "If we say that we have no sin, we deceive ourselves" (1 John 1:8). The way back is to own the sin: "If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (1 John 1:9). To confess is to admit it to God rather than hide it.

A son who has lied to his father is still his son. But until he owns up, there is a chill at the dinner table, and both of them know it.

Already forgiven

John writes to his "little children," and says why: "your sins are forgiven you for His name's sake" (1 John 2:12). The word means forgiven and still standing forgiven. So confessing does not save a believer again. It clears what broke his fellowship with the Father. And when he sins, "we have an Advocate with the Father, Jesus Christ the righteous" (1 John 2:1): Christ speaks for him.

David knew the same loss. "When I kept silent, my bones grew old Through my groaning all the day long. For day and night Your hand was heavy upon me" (Psalm 32:3-4). When he confessed, "You forgave the iniquity of my sin" (Psalm 32:5). He did not ask to be saved again. He asked, "Restore to me the joy of Your salvation" (Psalm 51:12). The salvation was still his. The joy was what he had lost.

The usual objection

"If we confess our sins, He is faithful and just to forgive us" (1 John 1:9). On this view a believer is forgiven only the sins he confesses, and one who dies with a sin unconfessed dies unforgiven and is lost.

John writes this to people whose sins already stand forgiven, and he counts himself among them: "If we confess." He is not telling saved people how to be saved. He is telling God's children how to walk with their Father again.

The words behind it