Sacred months and polytheists' manipulation of them

The number of months with God is twelve in accordance with God's law since the day He created the heavens and the earth. Of these four are holy. This is the straight reckoning. So do not exceed yourselves during them; but fight the idolaters to the end as they fight you in like manner; and remember, God is with those Who preserve themselves from evil and do the right.

Intercalating a month is adding to unbelief. The unbelievers are misguided by this, for they take the same month to be sacred one year and sacrilegious the next, thus making the number of months sanctified by God accord with theirs in order to make what God has forbidden, lawful. Attractive seem to them their evil deeds; but God does not show the unbelievers the way.