Qur'an & Hadith

In their endeavour to obviate certain disadvantages for their trade caused by the seasonal rotation of the lunar months, the pagan Arabs used to intercalate a thirteenth month in the third, sixth and eighth year of every eight-year period, with a view to making the lunar calendar more or less stationary, and thus roughly corresponding to the solar year. An acceptance of this unwarranted intercalation by the Muslims would have tied the Mecca pilgrimage as well as the fast of Ramadan to fixed seasons, and would thus have made, permanently, the performance of these religious duties either too exacting or too easy, and in either case the believers would have been offending against the spiritual purpose underlying these duties - which is the meaning of the words "do not sin against yourselves with regard to these [months]": i.e., by following, without any warrant from God, a custom devised by "those who ascribe divinity to aught beside Him", to whom the sequence refers.

This and the following verse must be read together. They condemn the arbitrary and selfish conduct of the Pagan Arabs, who, because there was a long-established custom of observing four months as those in which fighting was forbidden, changed the months about or added or deducted months when it suited them, to get an unfair advantage over the enemy. The four Prohibited Months were: Zul-qa'dah, Zul- hijjah, Muharram, and Rajab. If it suited them they postponed one of these months, and so a prohibited month became an ordinary month: while their opponents might hesitate to fight, they got an undue advantage. It also upset the security of the Month of Pilgrimage. This very ancient usage made for fair dealing all round, and its infraction by the Pagans is condemned. The question of a solar astronomical year as against the lunar Islamic year does not arise here. But it may be noted that the Arab year was roughly luni solar like the Hindu year, the months being lunar and the intercalation of a month every three years brought the year nearly but not accurately up to the solar reckoning. From the year of the Farewell Pilgrimage (A.H.10) the Islamic year was definitely fixed as a purely lunar year of roughly 354 days, the months being calculated by the actual appearance of the moon. After that, every month of the Islamic year came about 11 days earlier in the solar year, and thus the Islamic months travelled all round the seasons and the solar year.