And (as for) those of you who die and leave wives behind, they should keep themselves in waiting for four months and ten days; then when they have fully attained their term, there is no blame on you for what they do for themselves in a lawful manner; and Allah is aware of what you do.

And We appointed with Musa a time of thirty nights and completed them with ten (more), so the appointed time of his Lord was complete forty nights, and Musa said to his brother Haroun: Take my place among my people, and act well and do not follow the way of the mischief-makers.

Surely the number of months with Allah is twelve months in Allah's ordinance since the day when He created the heavens and the earth, of these four being sacred; that is the right reckoning; therefore be not unjust to yourselves regarding them, and fight the polytheists all together as they fight you all together; and know that Allah is with those who guard (against evil).