Is it permissible to fast on Saturday?

Scholars differed regarding fasting on Saturday. Some did not deem it reprehensible, while others disliked singling it out for fasting without fasting a day before or after it. This latter opinion is more probable, due to what was reported from the Prophet, peace and blessings be upon him, that he used to fast on Saturday and Sunday in opposition to the polytheists, and his prohibition against singling out Friday for fasting.