1For we know that if the earthly house of our tent is dissolved, we have a building from God, a house not made with hands, eternal, in the heavens. 2For most certainly in this we groan, longing to be clothed with our habitation which is from heaven, 3if indeed being clothed, we will not be found naked. 4For indeed we who are in this tent do groan, being burdened, not that we desire to be unclothed, but that we desire to be clothed, that what is mortal may be swallowed up by life. 5Now he who made us for this very thing is God, who also gave to us the down payment of the Spirit.
6Therefore we are always confident and know that while we are at home in the body, we are absent from the Lord; 7for we walk by faith, not by sight. 8We are courageous, I say, and are willing rather to be absent from the body and to be at home with the Lord. 9Therefore also we make it our aim, whether at home or absent, to be well pleasing to him. 10For we must all be revealed before the judgment seat of Christ that each one may receive the things in the body according to what he has done, whether good or bad.
11Knowing therefore the fear of the Lord, we persuade men, but we are revealed to God, and I hope that we are revealed also in your consciences. 12For we are not commending ourselves to you again, but speak as giving you occasion of boasting on our behalf, that you may have something to answer those who boast in appearance and not in heart. 13For if we are beside ourselves, it is for God. Or if we are of sober mind, it is for you. 14For the love of Christ compels us; because we judge thus: that one died for all, therefore all died. 15He died for all, that those who live should no longer live to themselves, but to him who for their sakes died and rose again.
16Therefore we know no one according to the flesh from now on. Even though we have known Christ according to the flesh, yet now we know him so no more. 17Therefore if anyone is in Christ, he is a new creation. The old things have passed away. Behold, all things have become new. 18But all things are of God, who reconciled us to himself through Jesus Christ, and gave to us the ministry of reconciliation; 19namely, that God was in Christ reconciling the world to himself, not reckoning to them their trespasses, and having committed to us the word of reconciliation.
20We are therefore ambassadors on behalf of Christ, as though God were entreating by us: we beg you on behalf of Christ, be reconciled to God. 21For him who knew no sin he made to be sin on our behalf, so that in him we might become the righteousness of God.
This verse serves as a purpose statement and a summary of what John has been saying in the previous paragraphs. He identifies his readers as “you who believe in the name of the Son of God.” They are those who have God’s testimony within them and have believed it. They are those possessing eternal life, the gift from God in response to their faith in His testimony.
The purpose of John’s writing the previous instructions is so that his readers can “know” (εἰδῆτε) by instruction that they have eternal life. This knowledge is not based on our feelings or our experiences. It is based on believing God’s testimony. Our confidence in our salvation comes from knowing what we believe, Whom we believe, and not how we live. Even when our works don’t measure up, we can have confidence in our salvation because of God’s promises. God does not want His children to wonder if they are saved or not. He wants every child to know without a doubt that they are His child. A believer, though possessing eternal life, cannot experience that life in this life apart from faith, apart from believing God’s testimony about Jesus and about eternal life in Him. A believer cannot have fellowship with God, cannot experience the mutual abiding relationship with God apart from believing those things God has affirmed about Jesus and eternal life. This is why John wrote the things contained in this last chapter.
A second purpose of John is to encourage his readers, and us, to keep believing in Jesus. Eternal life comes from Jesus and flows through the life of every believer. However, it cannot be experienced apart from faith in Jesus. As Paul describes it, we walk by faith (2 Cor 5:7). When a believer acts in unbelief and sins, that person is not “believing” in Jesus at that moment. All sin is an act of unbelief. Believers can fail to believe in Jesus. It is a choice that must be made moment-by-moment every day.