How did God provide for the poor saints in Jerusalem after the kitty ran out?
God provided for the poor saints in Jerusalem through the collections Paul took wherever he went. The common kitty had run empty because new believers were not adding fast enough, so God in His grace and goodness covered the need through those collections for the poor saints in Jerusalem.
Les explains that this was not the church as we understand it; it was a called-out group of Jewish believers. The Spirit had been poured on them, and they were all of one mind, living out of one common kitty. Since they did not have fifteen or twenty percent interest, that kitty either had to grow as new believers added to it or it would run out. It did run out, and new believers were not filling it fast enough. God in His grace and goodness covered that need because wherever Paul went, he took collections for the poor saints in Jerusalem.