the prohibition applies only to fasting it in isolation. If one fasts it together with Friday or with Sunday, there is no dislike, and this is the position adopted by Imam Ahmad, may Allah have mercy on him. In any case, should a person fast it alone he incurs no sin, yet it is better not to do so unless he joins to it either Friday or Sunday.

The hadith of Juwayriyyah reported in Sahih al-Bukhari and the hadith of Muhammad ibn ʿAbad recorded in Sahih Muslim both show that fasting on Saturday is not unlawful; it is permissible provided that one has also fasted on Friday. From this we learn that a person should not be a mere imitator who echoes whatever others say without examining the proofs and reconciling them. Some scholars look only at the apparent soundness of the chain of transmission and pronounce a report authentic without considering its content, yet scrutinizing the content is crucial. A single narrator’s mistake is easier to accept than an error that contradicts the principles of the Sharia or conflicts with clear, rigorously authenticated hadiths whose chains and texts are stronger.

For this reason, the student of knowledge—especially one devoted to hadith—must be alert: he should not judge a narration sound solely on the basis of an outwardly acceptable chain. He must examine its content: does it oppose established legal principles? does it clash with reports transmitted by reliable, firmly grounded authorities? If so, he should deem it anomalous and reject it, for, as I have told you, the likelihood of a single reporter erring is far less serious than assuming error on the part of the leading scholars or the well-established principles of the Sharia.

In short, fasting on Saturday as a voluntary act is not forbidden, but one ought not to single it out unless he fasts a day before it or a day after it. Allah is the One who grants success.