Leaven (sourdough), already-fermented dough used to start fermentation, was set overnight in unfermented dough, so by morning the whole batch was sour and risen. Three measures
is a lot: 3 sata (Hebrew: sesá(h)) = 1.5 Roman modius, about 13.13 litres: enough to make dough for about 160 people. What is special about leaven is that it is itself flour already fermented; mixing into the flour starts an irreversible process, with the original flour itself becoming leaven, until the original leaven is indistinguishable. The process is slow and incremental, but irresistible. Note the verb in Matthew 13:33—not put
the leaven in, but hid
it—stressing how the leaven has become invisible. Just as the mustard seed disappears into the soil, so the invisible
leaven disappears into the dough, yet in that hidden, humble operation, the whole batch rises. Listeners put off by Jesus’ seeming weakness might later see in these parables how Jesus’ humiliation and even his death will, paradoxically, be the way his people are brought into the kingdom.
Leaven (sourdough) was an already-fermented piece of dough used to start fermentation; the dough mixed with it would be left overnight, and by morning the whole batch was sour and risen. Three measures
is an unusually large quantity: 3 sata (Hebrew: sesá(h)) = 1.5 Roman modius, which amounts to 13.13 litres—enough to make dough for roughly 160 people.1
The special thing about leaven is that it is itself flour already fermented; once it is mixed into the flour its action cannot be undone. The active grain infects the adjacent portions, so that the grain itself becomes leaven: it gradually sours the whole mass until the original leaven is indistinguishable. The process is slow and incremental, but irresistible.2
The verb hid
in Matthew 13:33 is striking, though. Normally one says a woman puts the leaven into the flour, not that she hides
it. The word choice here stresses that the leaven is no longer visible. Just as the mustard seed is tiny and disappears into the soil, so the leaven is insignificant and disappears into the dough—yet through that hidden, humble beginning the whole batch rises. Listeners who had been put off by Jesus’ apparent weakness are startled by these parables: Jesus’ humiliation and even his death in Israel will, paradoxically, be the means by which his people are preserved and brought to conversion unto membership in the Father’s kingdom.3
33 He told them another parable. “The kingdom of heaven is like leaven that a woman took and hid in three measures of flour, till it was all leavened.”