“A new command I give you: Love one another. As I have loved you, so you must love one another. By this everyone will know that you are my disciples, if you love one another.”” - John 13:34-35
John and Peter, of all the disciples had a special relationship with Jesus. Jesus even allowed them time to commune with Abraham and Moses. John writes in a particular style that is also evident in his letters and in Revelations. Earlier, John had written that Jesus was the Word made flesh. That flesh was sacrificed by God, as a gift to those whom God loved, so that God could abide them Because eternal life is close proximity to God. And to perish is to be utterly riven from God.
Here, John is looking forward. The old commands of loving God and not following false idols is not extinguished by this 'new command' but it expresses the primacy required of following Jesus