When a person goes to Shul to say Yizkor they obligate themselves to give Tzedaka in memory of the deceased. Can this obligation be paid from Maaser or does it have to be paid from the persons personal funds? (sources please)
No written source, alas, but I have heard the following, if I remember it correctly, from Rabbi Yisrael Reisman (of Torah Vodaas and Agudath Israel of Madison, both in Brooklyn). Debts cannot be paid from funds of maaser. If one pledges to pay an amount to tz'daka, it's a debt, and he may not pay it from maaser. However, if one pledges to pay an amount to tz'daka and has in mind when he pledges that he's pledging not to pay from his own pocket but from maaser funds, then he may do so, as [I think the reasoning went] he has not pledged any amount from his own pocket, so has no personal debt. [Despite the lack of personal debt, he must pay pledged amount, I suspect.] As always, for a practical ruling, CYLOR.