If we just read these four little verses 13:31-35 of John's gospel, we'd think "Jesus is leaving" and "It's all on us now to elevate the world by the power of our love for one another." Good luck with that.
But the bigger story of the gospel of John is that Jesus is, as promised, present through the power of the Holy Spirit. The resurrecting power of God enables us to love one another, even our enemies, and to affirm that love is stronger than death. What is the "something we hold back against the night" in John's gospel? That not all good things must end someday. That what can't be cured (violence, hatred, and sorrow) will one day be redeemed. And that, in the meantime, "As Jesus has loved us, we also should love one another."