Question: I asked a child to deliver some mishloach manos packages for me on Purim for a small fee. Do I need to pay him on Purim or can it wait until the following day?
Answer: There is both a positive mitzva (Devarim 24:15) to pay workers on time as well as an aveira (Vayikra 19:13) not to withhold paying one’s worker’s wages. The Gemara (Bava Metzia 111a) writes that there another 5 potential mitzvos that one transgresses by not paying one’s worker on time.
The Gemara (ibid 112a) writes that the employer has only transgressed the aveira when they refuse to pay the employee when they ask for payment.
The Chafetz Chaim (Nesiv Hachesed 9:29) writes that if the employee doesn’t actually ask for his money, though comes for it, the employer must still pay that day.
The Chafetz Chaim (Ahavas Chesed 1:9:5) stresses that these halachos applies equally to children, though unfortunately people often take advantage of them and don’t pay them on time (See Shut Harashba 3:99). As children may be shy to specifically ask for the money, their employers need to be particularly careful to pay even if they don’t ask.While one can agree to pay one’s worker at a later date, it is certainly ideal to pay them that same day.