"As the Father has loved me, so have I loved you. Now remain in my love. If you keep my commands, you will remain in my love, just as I have kept my Father's commands and remain in his love. I have told you this so that my joy may be in you and that your joy may be complete. My command is this: Love each other as I have loved you. Greater love has no one than this: to lay down one's life for one's friends. You are my friends if you do what I command. I no longer call you servants, because a servant does not know his master's business. Instead, I have called you friends, for everything that I learned from my Father I have made known to you. You did not choose me, but I chose you and appointed you so that you might go and bear fruit—fruit that will last—and so that whatever you ask in my name the Father will give you. This is my command: Love each other."
In prior verses, Jesus used the analogy of a vine and branches to explain how behavior signifies a relationship with Him (John 15:1–11). In that discussion, Jesus reiterated that obedience to His teachings is an expected sign of those who truly believe (John 14:15). Among the more crucial commands given by Jesus is the requirement for believers to love one another (John 13:34). This instruction is echoed here.
It's tempting to read this edict from Jesus Christ with discouragement. Christ was sinless and perfect (Hebrews 4:15), so when He commands us to love each other the way He loved us, it's challenging. Worse, it can seem impossible: as fallible people, we don't always feel happy thoughts about others, even fellow Christians. The thought that we're obligated to feel perfect, joyful affection towards others is daunting. The prospect of martyrdom can be terrifying (John 15:13). However, that is not what Christ means in this statement.
Of course, His life and conduct are a born-again believer's goal (John 13:15). So far as we can, we want to respond to other people in a Christlike way. But Jesus is not telling believers "feel about other people the way I do." Nor is He demanding we be sinlessly, infallibly perfect. Rather, our love needs to echo the character of Christ's love. This involves two main ideas.
First, we should realize the "love" Jesus speaks of is practical, not emotional. We don't need to "feel warm thoughts" for others, but we do need to act lovingly towards them, even when they're hostile to us (Romans 12:17–21; Matthew 5:43–48). When this evening of discussion and teaching began, Jesus initiated it with an act of love: washing the feet of the disciples (John 13:3–5). Affection will sometimes grow as we serve others. But, even when it doesn't, the command to "love" remains.
Second, we are meant to echo the nature of Christ's love. This means humility (John 13:6), sacrifice (John 15:13), and service (John 13:35). Our approach to others, especially between fellow Christians (1 John 4:20–21), should be characterized by those traits. The idea of laying down one's life, stated in the next verse, means something more constant than a single act.