by Rabbi Yehonoson Dovid Hool
Q:
I pay my child’s babysitter at the end of the week, as per our agreement. Is this a kiyum of b’yomo titen scharo?
Rabbi Yehonoson Dovid Hool answered:
It depends. If the day you pay is the last day that she actually works, you have performed the mitzvah. (If the work ends during the day, you must pay before sundown; if it ends at night you must pay before morning.) If, however, you pay a day (or more) after the completion of the work, you have missed out on the mitzvah of a Beyomo.
This applies if this arrangement was agreed at the beginning of the employment – if it was not, and the babysitter requested pay on the day she finished work and you pushed it off to another day, in most cases you would have transgressed the mitzvah of Lo Tallin.