For the realization of the inability that permits moving to the substitute occurs at the time of the obligation, and how did you permit the fast before its time of obligation? We say: We only permitted him to move to the substitute based on apparent inability, for the apparent state of the insolvent person is the continuation of his insolvency and inability, just as we permitted making expiation with a substitute before the obligation of the original substitute. As for permitting the fast before its time of obligation, we have already mentioned it.

671- Issue: He said: "And whoever enters into the fast, then becomes able to afford the Hady, it is not required for him to exit the fast to the Hady, unless he wishes."

Al-Hasan, Qatada, Malik, and al-Shafi'i held this view. Ibn Abi Najih, Hammad, and al-Thawri said: If he becomes wealthy before completing the three days, he must perform the Hady; if he completes the three, he fasts the seven. It was also said: Whenever he is able to afford the Hady before the Day of Sacrifice, he should shift to it, whether he has fasted or not. If he finds it after the days of sacrifice have passed, the fast suffices him, whether he was able to afford the Hady or not; because he was able to afford the substitute [at the time of its obligation], so the substitute did not suffice him, just as if he had not fasted. Our argument is that it is a fast he entered into due to the absence of the Hady, [so if the Hady is found], he is not required to exit to it, like the fast of the seven, and upon this is derived the principle they used for their analogy, for [in that case] he had not yet commenced the fast.