Luke 13:20

Many think Christ is the leaven, for leaven which is made from meal, excels its kind in strength, not in appearance. So also Christ (according to the Fathers) shone forth above others equal in body, but unapproachable in excellence. The Holy Church therefore represents the type of the woman, of whom it is added, Which a woman, took and hid in three measures (sata) of meal, till the whole was leavened. But we are the meal of the woman which hide the Lord Jesus in the secrets of our hearts, until the heat of heavenly wisdom penetrates our innermost recesses. And since He says it was hid in three measures, it seems fitting that we should believe the Son of God to have been hid in the Law, veiled in the Prophets, manifested in the preaching of the Gospel. Here however I am invited to proceed farther, because our Lord Himself has taught us, that the leaven is the spiritual teaching of the Church. Now the Church sanctifies with its spiritual leaven the man who is renewed in body, soul, and spirit, seeing that these three are united in a certain equal measure of desire, and there breathes forth a complete harmony of the will. If then in this life the three measures abide in the same person until they are leavened and become one, there will be hereafter an incorruptible communion with them that love Christ.

The Satum is a kind of measure in use in the province of Palestine, holding about a bushel and a half.

Or, by the leaven He speaks of love, which kindles and stirs up the heart; the woman, that is, the Church, hides the leaven of love in three measures, because she bids us love God with all our hearts, all our minds, and all our strength. And this until the whole is leavened, that is, until love moves the whole soul into the perfection of itself, which begins here, but will be completed hereafter.