John 13:34-35 → Leviticus 19:18

At the Last Supper Jesus gives "a new commandment": "Love one another. As I have loved you, so you also must love one another" (13:34). The Johannine epistles will identify this as the love-command that is at once old — "the one we have had from the beginning" (1 John 2:7; 2 John 5) — and new, and the "old" command they have in view is the Lev 19:18 inheritance of the Torah. The dominical saying is therefore the source of the Johannine old-yet-new dialectic: the substance is the ancient covenant demand of Lev 19:18, but it is new in measure and ground. The newness is named in the comparative clause: not "as yourself" (Lev 19:18's kāmôkā) but "as I have loved you" — Christ's own self-giving love, soon to be displayed at the cross, becomes the new standard and the new enablement of neighbor-love. This is fulfillment, not abrogation: Jesus does not cancel Lev 19:18 but intensifies and Christologically internalizes it, raising the measure from self-love to His own laid-down life. The community-marker function ("by this everyone will know that you are My disciples," 13:35) makes the renewed Lev 19:18 the visible badge of the new covenant people. The telos is built into the text's own grammar: the imperative rests on a prior indicative — "as I have loved you" comes first — so that disciple-love is the overflow of Christ's love received, never a moralistic striving to earn it. The new-covenant heart-promise (Jer 31:33) stands behind this: the command Lev 19:18 always made is now finally doable because the Lover Himself indwells those He commands.