פירוש על עבודה זרה 67:4

The first question deals with a voluntary fast that a person might accept upon himself (this seems to have been a common pietistic practice). If he began the day not thinking that he was fasting, and then decided to fast and had not yet eaten, does this count as a fast? The second question is the topic we have been discussing. The third question is whether Moses wore priestly clothing during the seven days in which the altar was being consecrated despite the fact that he is not a priest.