It says that if anyone sins, "we have an advocate with the Father, Jesus Christ the righteous." The statement presents Jesus as the one who speaks for believers before the Father. See 1 John 2:1.
In 1 John 2:1–6, the writer explains why he is writing: to help his readers avoid sin, yet not fall into despair if they do sin. He points to Jesus Christ as the righteous one who speaks for them before the Father and as the effective sacrifice dealing with sin, reaching beyond one group to the whole world. This section continues the line of thought from 1 John 1:5–10, where the writer contrasts honest confession with claims that ignore wrongdoing. After warning against denying sin, he balances that realism with a strong aim: the community should not sin, and yet there is provision when they fail.
The passage holds two truths together: the writer’s goal is that his readers “may not sin,” and yet he assumes sin can still happen (“if anyone sins”). When it does, the help described is not self-justification but Jesus’ active role “with the Father” as a Counselor, and Jesus is explicitly called “the righteous” (verses 1–2).
A common mistake is to turn the wording into a slogan. The better reading keeps the phrase tied to the passage, the speaker, and the problem the book is addressing.
Start with 1 John 2:1, then read the surrounding section so the answer stays connected to the passage's flow.
1My little children, I write these things to you so that you may not sin. If anyone sins, we have a Counselor with the Father, Jesus Christ, the righteous.