[Pooya/Ali Commentary 2:184] Fasting is prescribed "for a certain number of days" - and as per the next verse they are the days of the month of Ramadan. The deeper benefits of fasting are gained when one is in good health. However, both in sickness and travel, these benefits are unlikely to be realised, therefore, exemption from fasting is provided, but a number of other days should be selected to fast in lieu of the obligatory fasts that have not been observed due to sickness or travel, and also a redemption (fidyah) should be effected by feeding a poor man for every missed fast. Aged people, nursing mothers and other cases in which the health is sure to be harmed by fasting can forego fasting altogether, but feed the poor instead, giving away the equivalent of one man's food daily for each fast missed. It is better to fast as well as feed the poor to obtain a greater return from Allah. The fidyah is a concession allowed to the sick and the old but if they know the deeper benefits of fasting they must fast instead of availing the concession. The Holy Prophet and the holy Imams used to give away whatever they had in the way of Allah but in the month of Ramadan, they were more liberal and open-handed, because the month of Ramadan is the month of Allah. Aqa Mahdi Puya says: Yutiquna means the ability to do something with great difficulty. The old and the sick come in this category. It is unreasonable to say that "so whoever witness this month (Ramadan) shall fast in it" (see next verse) cancels this passage. According to the holy Ahl ul Bayt this passage has not been abrogated. Tawaqa means ability with hardship, and tawa-a means ability with ease. This subtle difference was pointed out by Imam Jafar bin Muhammad al Sadiq. This passage applies to those who are able to fast but due to some weakness it is very difficult for them to do so.