What does John 13:34 mean?

There is some confusion over Jesus' reference to this commandment as "new." Earlier in His ministry, Jesus made it explicitly clear that love for others was a cornerstone of obedience to God (Matthew 22:36–40). The general instruction to love, then, is not being stated as if it's the first time it's being mentioned. The "newness" Jesus refers to here is in the sense of something refreshed, re-emphasized, or highlighted. The Greek term Jesus uses here, kainēn, leans heavily toward this version of "new."

This re-issued commandment is being given in the context of Jesus' washing of the disciples' feet (John 13:2–5). Jesus explained that if the Master acts as a humble servant, so too should those who follow Him (John 13:12–17). Here, Jesus doubles down on that idea by setting His own love as the standard to which all believers should aspire. In the next verse, Jesus will further explain the importance of acting in Christian love. In no uncertain terms, love—especially between fellow believers—is meant to be the primary and most powerful sign of one's Christian faith (John 13:35; 1 John 3:14).