Matthew 22:9

“Go you therefore to the partings of the highways, and as many as you shall find, bid to the marriage feast.”

So He told His servants to go to those who were outside the rebellious city, to those who would be found at the parting of the highways, the road intersections, where men presumably gathered, men who had received no invitation. And whoever they found there they were to bid to the marriage feast. The city authorities, with their cronies, may reject the king's son, but there would be many who would not (as His welcome into Jerusalem by the pilgrims had demonstrated). And by eating at His table they were indicating their loyalty to Him.

The disciples would have been in no doubt that this was to be their responsibility. They were to go to the very same kind of people as Jesus had gone to in Galilee, the poor, and the needy, and the lame, and the blind.