“By this all people will know that you are my disciples, if you have love for one another" (v35). Most ancient people thought divine beings (gods, angels, spirits, etc) were powerful, but Jesus revealed something surprising: the Creator loves His creation enough to die for us. This love – revealed in Jesus’ healing, teaching, dying, and rising again – is totally unique, and Jesus’ true disciples are marked the same way.
“Just as I have loved you, you also are to love one another” (v34). Jesus loved us sacrificially “to the end,” (v1), and this is how we are called to love one another.