Imam Malik, may Allah have mercy on him, said: He heard from the people of knowledge that they used to prohibit fasting on the day of doubt in Sha'ban with the intention of Ramadan, and they used to say that if someone fasted in Sha'ban on the day of doubt without sighting the moon, and then a trustworthy person testified that day was of Ramadan, then making up that fast is obligatory upon him. However, there is no objection in keeping a voluntary fast. Imam Malik, may Allah have mercy on him, said that we found the people of knowledge in our city saying the same.