by D. Martyn Lloyd-Jones

'I am glorified in them' (John 17:10).

So a Christian is a person who glorifies the Lord Jesus Christ by knowing that his sins are forgiven and by showing that he is one who has found peace with God. Surely Christ is glorified most of all when a man who is born in sin, who has been a sinner and has, perhaps, committed terrible sins, can nevertheless say, “I rejoice now in the knowledge that all my sins are forgiven.” He is not glorifying himself by saying that, but Christ. He cannot himself get rid of his sins; he cannot generate peace; he cannot quiet his own conscience; he cannot say he loves God. No, it is Christ and Christ alone who does it all, and the man who says that he knows his sins are forgiven is glorifying the Lord Jesus Christ. But the man who is doubtful whether he is forgiven or not is not glorifying Christ, neither is the man who says, “I hope my sins are forgiven,” nor yet the man who says, “I am living as good a life as I can in order to atone for my past.” The man who glorifies Christ is the man who can say, “Therefore being justified by faith, we have peace with God ... and rejoice in the hope of the glory of God” (Rom. 5:1-2).

Do you know that your sins are forgiven? Have you got assurance of salvation? Are you certain of it? For to the extent that you are, you glorify Christ, and to the extent that you are uncertain, you are not glorifying him. What proves that he has done the work he was sent to do is that we have the knowledge of sins forgiven and that we rejoice in it. He came very specially to do this, and therefore we glorify him by proving that he really has done it. It sounds a simple question, yet it is the profoundest question a man can ever face, so let me ask it again. Are you certain of God? Do you know God? Are you happy about your relationship to him? My dear friends, the Son of God not only came from heaven to earth, he went deliberately to the cross and suffered all the ignominy and shame of that cross in order that you and I might be certain, certain without any doubt at all, of our relationship to God as his children.

- Martyn Lloyd-Jones, The Assurance of our Salvation, Studies on John 17, page 286-287