John gives two doors and they're both still in the text: walk in the light, and confess. Notice verse 7 doesn't say walking in the light gets you fellowship with God first — it says fellowship with each other, because you cannot actually be close to people you're hiding from. Then verse 9 is the landing: God is faithful, meaning this isn't about His mood, and just, meaning the bill got paid by Jesus so forgiveness isn't Him going soft, it's Him being accurate. Real confession is specific, takes responsibility without a 'but,' and happens before you get caught — that's the difference between confession and arithmetic.
Think about it
What is one specific, true thing you've been keeping in the bag, and who is one person you could actually say it out loud to before this week is over?