Midrash su Levitico 27:2

1) (Vayikra 27:2) ("Speak to the children of Israel and say to them: A man if he utter a vow in your valuation of souls to the L–rd,"): The children of Israel assess, but gentiles do not assess. I might think, then, that they are (also) not assessed; it is, therefore, written "A man." These are the words of R. Meir. R. Meir said: If one verse includes, and the other excludes, why do I say they are assessed but do not assess? Because the power of the assessed is greater than that of the assessors. For a deaf-mute and a half-wit and a minor are assessed, but do not assess.

2) R. Yehudah says: The children of Israel are assessed, but gentiles are not assessed. I might think that they (also) do not assess; it is, therefore, written "A man." R. Yehudah said: If one verse includes, and the other excludes, why do I say they assess but are not assessed? Because the power of the assessors is greater than that of the assessed. For a tumtum (one of unknown sex) and a hermaphrodite assess, but are not assessed.

3) If "the children of Israel," I might think, only the children of Israel. Whence do I derive for inclusion proselytes and bondsmen? From "and say to them." I might think that (also) excluded is a minor (from twelve years and a day) who is able to utter (a vow distinctly). It is, therefore, written "if he utter a vow." It is written here "a vow," and elsewhere (Devarim 23:22) "a vow." Just as "a vow" here is subject to "if he utter," so, "a vow" there is subject to "if he utter." And just as "a vow" there is subject to "do not delay (to pay it"), so, "a vow" here is subject to "do not delay."