What is the ruling on fasting a day to complete Ramadhaan if people differ concerning fasting it? When should fasting be observed if this is valid?
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
Whoever misses a day of Ramadan should make up for it. Making it up should not be on a specific day but he should make up for it before the following Ramadan. The questioner said: “If people differ concerning fasting it”. This means that people are differing with regards to the beginning or end of the month. If the country does not depend, in determining the beginning or end of the month, upon astronomical calculations but rather on an actual sighting and they saw the moon and fasted twenty nine days, then they have done what they were ordered to do. Their fasting is correct and the doubt does not matter.
However, if they depend upon astronomical calculations and their fasting was less than what it should be according to the moon sighting or completing Sha’baan, then they should fast the missed days whether one or two days.
Allaah Knows best.
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