Albert Barnes Commentary Matthew 13:33

"Another parable spake he unto them; The kingdom of heaven is like unto leaven, which a woman took, and hid in three measures of meal, till it was all leavened." — Matthew 13:33 (ASV)

The kingdom of heaven. This means the same as in the last parable, perhaps, however, intending to denote more precisely the secret and hidden nature of piety in the soul. The other parable declared that the gospel would greatly spread, and that piety in the heart would greatly increase. This declares the way or mode in which it would be done. It is secret, silent, steady; pervading all the faculties of the soul, and all the kingdoms of the world, as leaven, or yeast, though hidden in the flour, and though deposited only in one place, works silently until all the mass is brought under its influence.

Three measures. These were small measures, but the particular amount is of no consequence to the story. Nor is anything to be drawn from the fact that three are mentioned. It is mentioned as a circumstance giving interest to the parable, but designed to convey no spiritual instruction. The measure mentioned here probably contained about a peck and a half.