Pahlavi Texts, Part III (SBE24), E.W. West, tr. [1885], at sacred-texts.com
1. The eighty-third subject is this, that it is requisite to abstain from the keeping of fasts. 2. For, in our religion, it is not proper that they should not eat every day or anything, because it would be a sin not to do so.
3. With us the keeping of fast is this, that we keep fast from committing sin with our eyes and tongue and ears and hands and feet. 4. Some people are striving about it, so that they may not eat anything all day, and they practise abstinence from eating anything. 5. For us it is also necessary to make an effort, so that we may not think, or speak, or commit any sin; and it is necessary that no bad action should proceed from our hands, or tongue, or ears, or feet, which would be a sin owing to them.
6. Since I have spoken in this manner, and have brought forward the fasting of the seven members of the body, that which, in other religions, is fasting owing to not eating is, in our religion, fasting owing to not committing sin.