2 Beloved, now we are children of God; and it has not yet been revealed what we shall be, but we know that when He is revealed, we shall be like Him, for we shall see Him as He is. 3 And everyone who has this hope in Him purifies himself, just as He is pure.

This is such a marvelous text. We are the children of God, right now, if you believe in Jesus Christ and you have been redeemed and justified, you are now a child of God. It hasn’t been revealed what we shall be. In other words, I can’t look at you and tell that you’re a child of God. We haven’t yet experienced what the Apostle Paul calls the manifestation of the son’s of God. The world around us doesn’t know. We go to work or to school and people who look at you don’t know you’re a child of God; there’s no way they can tell that. It hasn’t been revealed. We are sort of hidden at this time. But we know this, that when He is revealed, looking at the second coming, when Jesus is revealed, when He comes He comes for and with His saints. We know that the whole world is going to see Him. In fact, there is a picture in Revelation 19 of Jesus coming out of Heaven riding a white horse and all the saints in white robes coming after Him as He comes to establish His kingdom on earth. There is coming a day the glorious manifestation of the children of God, Romans 8 calls it, when the whole world is going to find out who we really are and when that happens we are going to be like Him for we shall see Him as He is. This incredible promise is our hope. Someday we are going to be like Jesus Christ. We’ll not only experience it but everyone will see it and the truth will then be revealed that we are the children of God. He closes these two verses by saying everyone who has this hope in him purifies himself, just as He is pure. That means that if you live in the anticipation of the coming Christ it changes the way you live. It alters the speed in which we drive when we see the police car in the middle of the freeway. How much then should it alter the way we live when we anticipate the imminent return of Jesus Christ and we don’t know even when He’s coming. He could come at anytime. The fact that we know He is coming and He is perfectly pure and that when He does come He’s going to make us like Himself, that ought to be a marvelous motivation for our own purity. Live in the light of the coming of Christ and He’s coming at a time you don’t know. Make sure that when He does come He finds you living in a pure way.  – John MacArthur