JESUS WAS GAINING in popularity with the people, but it was upsetting the established religious order. His opponents wanted to discredit him. If they could have, they would have launched a smear campaign on social media. Instead, they had to go old school and try to humiliate him in public debate.

We all know how that went.

Once, an expert on the Mosaic Law put Jesus to the test by publicly asking him a question. “Teacher,” he began, with feigned respect, “what must I do to inherit eternal life?” (Luke 10:25, NIV). Jesus, of course, could have answered easily. But knowing the man’s intentions, he turned the question around. In essence, he said, “Well, you’re the expert in the Law. What do you think?”

The legal expert could have replied, “No fair, I asked you first!” But I suspect that Jesus’ question provoked the man’s pride, his own need to show off what he knew. This was his area of expertise, so he answered confidently, quoting both Deuteronomy and Leviticus: “‘Love the Lord your God with all your heart and with all your soul and with all your strength and with all your mind’ and, ‘Love your neighbor as yourself'” (Luke 10:27).

“Bingo,” Jesus replied. “Then just do that.” After all, Jesus himself taught that these two commandments captured the very heart of the Hebrew Scriptures (Matt 22:37-40). The legal expert, in other words, could not have given a better answer. The subtext of Jesus’ response, however, embarrassed the man: If you already knew the answer, why did you ask?

Unexpectedly finding his own integrity called into question, the lawyer felt the need to justify himself and deflect any criticism. Hurriedly, therefore, he came up with another question: “And, uh, who is my neighbor?” Let’s see you wiggle out of that one, buddy.

This time, Jesus told a parable, a story that would irresistibly capture the imaginations of his hearers. We know it as the parable of the Good Samaritan, in which both a priest and a Levite happen upon a wounded and dying victim of a robbery, and pass by as if they hadn’t seen him. Only a Samaritan — whom the lawyer would have considered a detestable enemy — stopped to help, and sacrificially so.

At the end of the story, Jesus again put the legal expert on the spot. No doubt, if Jesus had said, “The Samaritan is your neighbor,” the lawyer would have pounced triumphantly. Instead, Jesus asked, “Which one of the three men was a neighbor to the victim?”

The lawyer was forced to give the only answer he could: “The one who showed mercy.”

“Right again,” said Jesus. “Now go do it.”

Luke doesn’t tell us the state of the lawyer’s heart. Did he slink away in defeat, thinking, “Just wait, Jesus. I’ll get you next time”? Or did his heart soften with new conviction and insight before he said, “The one who had mercy”? There’s no way to know.

But one thing is certain from the story: it’s possible to know what God commands and not do it.

IN CHAPTER TWO of his letter, as we’ve seen, the apostle John teaches that a true relationship to God — indeed, love for God — is demonstrated in one’s obedience to what he commands. But such loving obedience is not just vertical, not just limited to one’s relationship to God. As with the two great commandments, obedience to God has a horizontal dimension as well. Drawing once more upon the contrast between light and darkness, John gives voice to that horizontal aspect of love by contrasting love with hate:

Dear friends, I am not writing you a new command but an old one, which you have had since the beginning. This old command is the message you have heard. Yet I am writing you a new command; its truth is seen in him and in you, because the darkness is passing and the true light is already shining. Anyone who claims to be in the light but hates a brother or sister is still in the darkness. Anyone who loves their brother and sister lives in the light, and there is nothing in them to make them stumble. But anyone who hates a brother or sister is in the darkness and walks around in the darkness. They do not know where they are going, because the darkness has blinded them. (1 John 2:7-11)

We’ll explore these verses a little at a time. Note that while John has been writing in more general terms about light and darkness, truth and lies, what “we” know and what some people say, he turns momentarily in a more direct and personal direction. Though in the New International Version John addresses his readers as “dear friends,” we don’t want to miss that the word he actually uses is related to his word for love, agape. Literally, he is calling them his beloved. As we’ll see shortly, Jesus commanded his followers to love one another (John 15:12), and that is the spirit in which John himself writes.

He doesn’t want them to think that his message to them is entirely new. He calls it an “old command,” one they’ve had “from the beginning.” But the beginning of what? He identifies the old command with “the message you have heard” — and in so doing, points back at least to the beginning of their lives as believers, when they first heard and received the gospel.

But he probably means more than this. John’s understanding of the gospel is expansive, cosmic. Believing in and following Jesus means being drawn into a story that reaches back even to a time before the universe was created. It includes not only the teaching about Jesus, but the teaching of Jesus. And the teaching of Jesus is itself rooted in ancient history, the story of God’s covenant relationship to his people.

What Jesus taught, what Jesus embodied and modeled, was rooted in what was already known. The legal expert knew it, even if he didn’t practice it. If John’s readers or anyone in the community wanted to claim that they really knew God, that they walked in the light, that they loved the God who is light, then they would have to live like the one who declared himself to be the light of the world. Love God? Then love your neighbor, love one another.

Right, Jesus tells the man who wanted to save face. You know this stuff already. Now go do it.