And he is the propitiation for our sins: the adding of these words, shows that our Lord grounds his intercession for pardon of sin unto penitent believers, upon his having made atonement for them before; and therefore that he doth not herein merely supplicate for favour, but (which is the proper business of an advocate) plead law and right; agreeably to what is said above, 1 John 1:9. And not for ours only, but also for the sins of the whole world; nor is his undertaking herein limited to any select persons among believers, but he must be understood to be an Advocate for all, for whom he is effectually a Propitiation, i.e. for all that truly believe in him, \Romans 3:25\ all the world over.
Related Commentaries of 1 John 2:2
1 John 2:2
2 And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world.