From when are all people permitted in leket? From when the gropers go. In peret and oleilos? From when the poor go through the vineyard and return. And in olives? From when the second rains fall. Said R' Yehudah: But are there not people who do not harvest their olives until after the second rains? Rather, [they are permitted] when the poor person goes out and is unable to bring back four issars' worth.