Is one allowed to give tzedaka for ma’aser on the condition that it apply to future earnings?
For example, if someone gets a paycheck on the 30th of the month and wants to give tzedaka on the 20th,
can it be given (on the 20th) with the intention to deduct ma’aser from the upcoming paycheck?
We are allowed to give maaser for future earnings. There is however a preference to stipulate it when accepting to give maser that it he can take it off even from future earnings.
Noda B’yehudah brought in Pischei Teshuva 249-1, Shevet Halevi 2-133(9), Ahavas Chesed 2-12-2, B’orach Tzedakah 2-10.