Sunago means, approximately, collect or gather or invite or welcome. Jesus says we should do this thing (sunago) to the stranger (xenos). From the Greek work we get the English word synagogue, the place where you sunago.
I think the best way to get a firm grasp on the word is to see it in context. It shows up 59 times in the New Testament, including 24 occurrences in Matthew’s Gospel. Here are the 24, with a sentence for each to identify the context.
I. Gather people together for an assembly of some kind
1. Matthew 2:4 : Herod assembled the chief priests and scribes and asked where the Messiah was to be born.
2. Matthew 13:2 : Large crowds were gathered together around him.
3. Matthew 22:34 : When the Pharisees heard that Jesus had silenced the Sadducees, they gathered together.
4. Matthew 22:41 : When the Pharisees were gathered together, Jesus questioned them.
5. Matthew 24:28 : Wherever the corpse is, the vultures will gather.
6. Matthew 25:32 : The Last Judgment passage begins saying that the Son of Man will sit on his throne, and all the nations will be assembled before him.
7. Matthew 26:3 : The chief priests and elders assembled in the palace.
8. Matthew 26:57 : They led Jesus to Caiaphas, where the priests and elders were assembled.
9. Matthew 27:17 : When the people were assembled, Pilate spoke to them.
10. Matthew 27:27 : The soldiers took Jesus into the praetorium and gathered the whole cohort around him.
11. Matthew 27:62 : The next day, the chief priests and the Pharisees gathered before Pilate.
12. Matthew 28:12 : When the chief priests hear what the guards had to say, they assembled the elders and took counsel.
II. Harvest a crop
1. Matthew 3:12 : He will gather the wheat into his barn, but the chaff he will burn.
2. Matthew 6:26 Look at the birds … they don’t gather anything into the barns.
3. Matthew 13:30 : Collect (sullego) the weeds and bundle them for burning, but gather (sunago) the wheat into my barn.
4. Matthew 13:47 : The kingdom of heaven is like a net thrown into the sea, which collects every kind of fish. They haul it all ashore, sort it, and throw out the bad.
5. Matthew 25:24 : Master, I knew that you harvested where you hadn’t planted, and gathered where you hadn’t scattered, and I was scared.
6. Matthew 25:26 : You knew that I harvest where I didn’t plant and gather where I didn’t scatter, and yet you didn’t even put the money in a bank?
III. Worth individual careful attention
1. Matthew 12:30 : Whoever is not with me is against me. And whoever does not gather with me, scatters. (The word for scatter is scorpiz-. There’s gathering like a synagogue, and there’s scattering like a scorpion.)
2. Matthew 18:20 : Wherever two or three gather together in my name, there I am in their midst. (Unless they tell me to get lost.)
3. Matthew 22:10 : For the wedding feast, servants went out and gathered all the people they could find, good and bad alike, and filled the hall. (What’s the garment that you have to wear to this wedding? Put on Christ, and welcome the strays from the highways and byways who were invited at the last minute. If you sneer at the new guests, the bouncers will not toss them out; the bouncers will toss you.)
The lines that raised the question in the first place
1. Matthew 25:35 : I was a stranger, and you [sunago] me.
2. Matthew 25:38 : When did we see you as a stranger and [sunago] you?
3. Matthew 25:43 : I was a stranger, and you did not [sunago] me.
[In the fourth reference to strangers in this passage from Matthew 25:31-46, there’s only one general verb. It says that when you saw me hungry or thirsty or as a stranger or naked or sick or in prison, you did not minister – in Greek, diakoneo – to me.]
1. The word sunago appears 59 times in the New Testament, including 24 times in Matthew’s Gospel. Of those 24, half (12) refer to assemblies of people, and a quarter (6) collecting crops. Three are in the passage about the Lord’s precepts (serve the hungry, thirsty, strangers, naked, sick, & imprisoned). And three require individual attention.
2. This [sunago] is one way to serve. It’s a service. People want it.
3. The opposite of [sunago] is scattering, like a scorpion.
4. This service is more psychological than “corporal.” Welcome, invite, include, gather with.
5. It’s proactive. None of the uses of the word sound like someone sitting at home with tea and cakes ready in case someone stops by. This action (perhaps hospitality) is not passive; it’s active, up and out, collect, gather, assemble, invite, serve.
6. The word often refers to an assembly of some kind. You got your friends together and didn’t invite me. You called a meeting and didn’t notify me. The gathering might be good (a feast, a presentation), or might be bad (vultures at a corpse, plotters plotting violence), but there’s a gathering of like-minded people. It’s fundamentally social, not individual.
7. It is plausible that the word often refers to preaching the Gospel. The text surrounding these uses of sunago does not say “preaching the Gospel”; but it does refer to whatever you’re supposed to do about the Kingdom of God in our midst: gather in crops (sunago), pull in nets of fish (sunago), put things in barns (sunago). It’s a little odd: this harvest activity includes keeping the good and discarding or burning the bad – while the passage in Matthew about six precepts doesn’t refer to burning up the weeds, and says instead that the workers who fail to xx (?? – sunago) the stranger are consigned to the fire.
8. Two of the references to gathering a harvest are just a few lines before the passage with six precepts. That is, in Matthew 25:24-26, we read about the man with one “talent” that he didn’t use wisely; he was afraid of the Master who harvested what he hadn’t planted and gathered (sunago) where he hadn’t scattered. Then in Matthew 25:31-46, we read four times about welcoming (?? – the verb is sunago) strangers.
9. The three lines that need careful scrutiny are:
(a) Matthew 12:30 : Whoever is not with me is against me. And whoever does not gather with me, scatters. (The word for scatter is scorpiz-. There’s gathering like a synagogue, and there’s scattering like a scorpion.)
(b) Matthew 18:20 : Wherever two or three gather together in my name, there I am in their midst. (Unless they tell me to get lost.)
(c) Matthew 22:10 : For the wedding feast, servants went out and gathered all the people they could find, good and bad alike, and filled the hall. (What’s the garment that you have to wear to this wedding? Put on Christ, and welcome the strays from the highways and byways who were invited at the last minute. If you sneer at the new guests, the bouncers will not toss them out; the bouncers will toss you.)