Thus, leasing trees in order to tend them and take their fruit is comparable to hiring a wet nurse for her milk. The only hiring contract explicitly mentioned in the Quran is that of a wet nurse, in the words of Allah, glorified be He:

“If they breastfeed for you, give them their payment.”

Some jurists, believing that a hiring contract can concern only a usufruct and not a tangible substance, yet recognizing the permissibility of hiring a wet nurse, said: “The subject of the contract is placing the child in her lap; the milk is included implicitly and incidentally, like the water in a well.” This flies in the face of both reason and sensory experience. We know beyond question that the milk is the object of the contract, as Allah indicates by His words:

“If they breastfeed for you.”

Holding the child in her lap, if done, is merely a means to that end.

The underlying reason is simply what I have mentioned: a yield that is replenished while its source remains is treated as a usufruct. This is not a sale in the strict sense, for Allah calls the compensation a payment for services, not a purchase price. This differs from the case where the milk has already been drawn: exchanging it for compensation is then called only a sale, because the yield is not being obtained from its source in the way that a usufruct is obtained from its source.

Thus, tangible yields that can be separated from their sources have two states. In one, they resemble pure usufructs: while still attached to their sources, they are obtained in the same way as a usufruct. In the other, they resemble tangible goods as such: once separated, possession of them is taken in the same way as possession of tangible goods.

If the owner of the trees is the one who waters and tends them until the fruit is fit for harvest, he is selling nothing but fruit, just as if he were the one who tills the land