We all know about the Good Samaritan. It's a memorable story, also for the lesson it so clearly teaches in answer to that question: "Who is my neighbour?" We know the parable and its lesson, yet we also know how hard it is to show this kind of love. How difficult, especially when we're in the uncomfortable position of actually having to do something!

Yet this is the call of the Scriptures: that God's people be busy with loving not just those who love them in return, but loving all – neighbours and visitors and strangers alike. That's what we're exhorted in Hebrews 13, where the writer begins his closing words to the congregation: "Keep on loving each other as brothers" (v. 1). If you've been sprinkled with Christ's blood, then you'll love your fellow members in the family of Christ.

The author then goes on to speak of other ways of showing love, the first of which is that command to "entertain strangers." The Greek term that's used here is a compound word and it means literally "the love-of-strangers." Don't neglect it, we're told! So what is this activity? It's being welcoming to all, like by reaching out to those fellow saints you're not so familiar with or by offering kindness to the unbelievers whom God places on your path.

And this is what the saints have always done, for in "so doing some people have entertained angels without knowing it" (v. 2). It's just a passing allusion, but one that the "Hebrews" would've picked up on. Probably the first example that popped into their minds would've been Genesis 18, where Abraham is active in "the love-of-strangers." For he welcomes to his tents those three men who suddenly drop in; he prepares a meal for them, even waits on them like a lowly servant would.

We know the identity of these three visitors, of course: two are angels, and the third is said to be none other than "the LORD." But Abraham doesn't know and that's the whole point. These three travellers could've been anyone, from anywhere, but that doesn't hinder Abraham's work of hospitality.

More examples of unsuspecting hospitality to angels could be brought forward, from Genesis 19 or Judges 6 or Judges 13. The impression is that the saints were used to doing this, welcoming perfect "strangers." Surely it wasn't always convenient for those who hosted. Being hospitable meant incurring costs. Yet they honoured the obligation to love their neighbour.

The question some people want to ask when they read this text is: "So will angels in disguise appear to us today?" And there are stories to that effect, told by people who are almost certain they once encountered an angel: that person in the snowstorm, that beggar on the sidewalk, that blind man on the bus.

Is it impossible that God would place an "undercover angel" on our path today? We could debate the question. But notice the text isn't teaching us to expect such appearances from heaven. Instead, the whole lesson is about how we treat the people around us here on earth. The Holy Spirit wants us to ask a different question: "So what about the people constantly coming in and out of my life? Do I love them? Do I welcome them? And how can I better build them up?"

The illustration from the past is brought forward by the Spirit to show us the abiding importance of neighbour love. That great "cloud of witnesses" shows us how it's done. Many things have changed from the days of Abraham, but not this!

God is telling us that true love reaches across a great distance. Sometimes that distance is in the church, where there might be brothers and sisters in Christ who wrestle with loneliness, who are in need of some kind of help, or who've strayed to the fringes. Perhaps we don't really know them, but that shouldn't stop us. We must love these "strangers" in our midst, open our door to them, and respond to their needs in concrete ways.

And this love has to reach across an even greater distance, out into the world. For the world is full of "strangers." When we meet them, we have no idea who they are. They could be anyone, from anywhere. They could look odd, they could be down and out, or even be followers of different religions. What should we do?

We ought to treat them with love. We ought to treat them as if the holy angels were in our midst, as if these people were sent by God himself to walk among us – indeed, God has sent these strangers! So let's not neglect to welcome them.