I love what the vicar, Dyson Hague, says about “At-One-Ment by Propitiation” and substitutionary atonement in John’s Gospel:

According to St. John, the death of the Lord Jesus Christ was propitiatory, substitutionary, purificatory.  It was the Hilasmos; the objective ground for the remission of our sins.

The narrow and superficial treatment of modernism, which, if it does not deny the Johannine authorship of the fourth Gospel and the Revelation, at least insinuates that the death of Christ has no parallel place in the writings of St. John to that which it has in the writings of St. Peter and St. Paul, and the other New Testament authors, is entirely contradicted by the plain statements of the Word itself.

The glory of the world to come is the sacrificed Lamb.  The glory of heaven is not the risen or ascended Lord, but the Lamb that was slaughtered (Rev. 5:6-12; 7:10; 21:23, etc.).  The foremost figure in the Johannine Gospel is the Lamb of God which taketh away the sin of the world, who lifts the sin-burden by expiating it as the Sin-Bearer.  The center of the Johannine evangel is not the teaching Christ, but the uplifted Christ, whose death is to draw as a magnet the hearts of mankind, and whose life as the Good Shepherd is laid down for the sheep.  (John 12:32; 10:11-15).

No one who fairly faces the text could deny that the objective ground for the forgiveness of sins, in the mind of St. John, is the death of Christ, and that the most fundamental conception of sacrifice and expiation is found in the writings of him who wrote by the Spirit of God, “He is the propitiation of our sins, and not for ours only” (I John 2:2).  “Hereby perceive we the love of God because he laid down His life for us” (I John 3:16). “Herein is love,” etc. (I John 4:10).

The propitiatory character of the blood, the substitutionary character of the atonement, and, above all, the expiating character of the work of Christ on Calvary, clearly are most indubitably set forth in the threefoldness of the historic, didactic, and prophetic writings of St. John.