Ruling 1578 — Fasting (Ṣawm)

If someone ascribes to Allah the Exalted, the Most Noble Prophet (Ṣ), [or the Infallible Imams (ʿA)] something that he knows to be false, and afterwards he realises that what he said was true, and he knew that this act would invalidate his fast, he must, based on obligatory precaution, complete his fast and keep a qaḍāʾ fast as well.