http://bible.org/article/non-pauline-epistles
The book of First John:
2:1 (My little children, I am writing these things to you so that you may not sin.) But if anyone does sin, we have an advocate with the Father, Jesus Christ the righteous One; 2:2 and he himself is the atoning sacrifice for our sins, and not only for our sins but also for the whole world.
My little children, I am writing these things to you.
You = “my little children”, the young Christians.
Our = you + me.
Jesus is the atoning sacrifice for our sins (John + the young Christian believers), and also for the whole world.
Who is the whole world?
Everyone else.
Jesus is the atoning sacrifice for the sins of the whole world. Not some of them. All of them.