Commentary for Menachot 13:4

לא יפחות מדינר זהב – and he that would state a gold coin. For if not, perhaps he states a piece of gold bar, that is a piece of gold.

Introduction Today’s mishnah deals with a person who volunteers to bring an unspecified amount of money as a donation to the Temple.

נחושת לא יפחות ממעה כסף – that he should bring copper that is worth a Maah of silver (i.e., a Maah is a small silver coin worth thirty-two peruta or one-sixth of a dinar = the Biblical gerah).

“I take upon myself to offer gold,” he must bring not less than a golden denar. Since the smallest gold coin is a golden denar, the person who pledges to bring gold must bring at least a golden denar.

פירשתי – such and such [an amount of] gold.

“Silver,” he must bring not less than a silver denar. The same rule applies when it comes to silver.

ואיני יודע כמה פירשתי – he should bring so much until that he would himself would know that he never intended for so much.

“Copper,” he must bring not less than [the value of] a silver maah. If someone pledges to bring copper, he must bring copper that is equivalent in value to one silver maah. A maah is 1/24 of a sela, and a sela is equivalent to 4 denars, so a maah is 1/6 of a denar.

[If he said] “I specified [how much I would bring] but I do not know what I specified,” he must bring until he says, “I certainly did not intend to give so much!” In this case, the person doesn’t remember how much he pledged. He must therefore bring the maximum amount he might have possibly pledged. In other words, we might say to him, “Might you have pledged 10 denars?” If he says yes, then we would say, “Might you have pledged 100 denars?” If he says yes, then the number keeps going up until he hits a number that he knows he definitely didn’t pledge. We should note that in all of these cases we are dealing with a person who honestly wants to fulfill his vow. There is no concern that the person might lie and say “I could not have possibly pledged to bring such a large amount” when he really might have, because if we were concerned about him lying, he could have just lied and said that he remembered having pledged a lower amount. Rather, in all of these mishnayot we are dealing with a person who honestly wants to figure out how much money he owes to the Temple.