But with sacrificial offerings it is not so. Should one say, ‘I take upon myself [to give] the offering of this metzora’ — if the metzora was poor, he brings the offering of a poor man; [if he was] rich, he brings the offering of a rich man. Rabbi says: I say that even in the case of arachin it is so. For why is it that a poor man who vowed the erech of a rich man gives the erech of a poor man? Because the rich man is not at all obligated. But [if] the rich man said, ‘I take upon myself [to give] my erech,’ and the poor man overheard [him] and said, ‘I take upon myself [to give] what this man said’ — he gives the erech of a rich man. [If] he was poor and became rich, or [he was] rich and became poor — he gives the erech of a rich man. R’ Yehudah says: Even a poor man who became rich and then became poor again gives the erech of a rich man.