1 John 2:1-6
1 “My little children, I am writing these things to you so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous; 2 and He Himself is the propitiation for our sins; and not for ours only, but also for the sins of the whole world.3 By this we know that we have come to know Him, if we keep His commandments. 4 The one who says, “I have come to know Him,” and does not keep His commandments, is a liar, and the truth is not in him; 5 but whoever follows His word, in him the love of God has truly been perfected. By this we know that we are in Him: 6 the one who says that he remains in Him ought, himself also, walk just as He walked.”
My little children: John goes from addressing the group generally in chapter 1 to specifically addressing Christians. Christians have an advocate for when they sin: Jesus Christ. In contrast to those who were being emphasized with 1 John 1:9, Christians do not need more forgiveness or cleansing because Jesus forever stands in our defense.
Propitiation: The sacrifice of Christ is a propitiation for the sins of the world. In contrast to the Old Testament concept of atonement in which sin was merely covered, Jesus actually took away the sins of the world. His is the only sacrifice that could actually completely satisfy God. This means that the Old Testament sacrifices are no longer needed because the perfect sacrifice has occurred. Because this perfect sacrifice has arrived, we are totally forgiven and cleansed from all unrighteousness (1 John 1:9).
Whole world: This is not a reference to universalism. Rather, it is referring to the total scope of Christ’s work for the sins of the entire world. The blood of Christ is sufficient to take away the sins of all who believe in Him. But faith is needed in order for forgiveness to be a reality for the individual.
Keep His Commandments: John is not speaking of the Old Covenant law. This would contradict the entire message of the New Testament. Rather, John is speaking of new commandments from Jesus: Believe in Jesus and love one another (1 John 3:23). Those who believe in Jesus are born again and can love with the love of God. This is because believers abide or live in God. By this reality we can know that we are in Him.
As He walked: These words are not speaking of miracles such as walking on water or resurrecting the deceased. In context, John is upholding love as the greatest work to be accomplished. Believers are to walk as Jesus did by loving as He loved.