1,218. Lending Borrowed Property
185:1 If one person borrows or rents an animal or moveable property from another person, he is not allowed to lend or rent it to a third party without the owner's permission. This is true even of books, which have a mitzvah to lend them. We do not assume that the owners will approve because a mitzvah is being done with their property, since they may not want this thing to be lent to a third party, whom they may not consider trustworthy. However, it is permitted for one who has borrowed a book to allow another to learn from it in the borrower's home so long as he uses it by himself, rather than both of them using it together. If it is known that the owner trusts the borrower's judgment in such matters, then the borrower may lend to a third party and a renter may rent to a third party.
185:2 It is a mitzvah to pay hired workers their wages at the proper time. If one delays, he violates a negative commandment, as per Deuteronomy 24:15, "Give him his wages on the designated day and do not let the sun go down on it." Similarly, it is a mitzvah to pay for renting an animal or utensils at the proper time, and if one delays, he violates a negative commandment, as per Deuteronomy 24:14, "Do not oppress a poor and needy hired hand...give him his wages on their designated day."
What is considered the proper time to pay? If the worker finished the job during the day, the time is the entire day. If the day passes and the employer didn't pay him, he has violated "Give him his wages on the proper day and do not let the sun go down on it." If the worker completed his work after the day has ended and night has started, then the time to pay is the entire night. If the night passes and he hasn't paid, he transgresses Leviticus 19:13, "The wages of a hired worker shall not remain with you...until the morning." Similarly, one who is hired by the week, by the month, or by the year, if he completes his work by day, he may be paid the entire day; if he completes his work by night, he may be paid the entire night, no later.