then, if we say that the contract is valid and that he has the option upon seeing it, the contract is lawful. But if we say that the contract is invalid, then the contract is unlawful, and both the lessee and the lessor are sinful, because they have done something unlawful.

According to the established position of the school, it is absolutely invalid. Accordingly, entering into such a contract is unlawful; and if, upon seeing the property, the lessee is satisfied with it, he must renew the contract.

Issue: Anything hired for its sound is to be ascertained by hearing it. For example, if you hire an alarm clock so that it will alert you for some task, you must hear it; merely seeing it is not sufficient. Unless, for instance, it is of a known make whose alarm sound is well known; in that case, this may perhaps suffice. Yet even then, the tone of that particular type may have been altered, or it may have developed a fault, so it must be heard.

If one hires a rooster for its call, its sound must likewise be heard, for some roosters have a pleasant voice while others do not—they are hoarse. They differ greatly in this respect. But if one hires a rooster to wake him for prayer, this is not valid, because the benefit cannot be obtained: the rooster may sleep on some days.

Thus, a rooster may be hired for its sound; but hiring it on the basis that it will wake you for prayer is not possible, because it is not possible to ensure receipt of that benefit from it.

In summary, the leased property must be known. Whatever is hired on the basis of sight must be inspected; whatever is hired for its sound must be heard; whatever cannot be ascertained except by sight must be inspected; and whatever can be ascertained by description, description is sufficient for it.