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.
What has happened to you, O believers, that when you are asked to set out in the cause of God your feet begin to drag? Do you find the life of the world so pleasing that you forget the life to come? Yet the profit of the life of this world is but meagre as compared to the life to come.
Unless you go out (to strive), God will inflict grievous punishment on you, and bring other people in your place, and you will not be able to harm Him in the least, for God has the power over all things.
If you do not help (the Prophet, remember) God had helped him when the infidels had forced him to leave (and he was) one of two. When both of them were in the cave, he said to his companion: "Do not grieve, for God is with us." Then God sent divine peace on him, and invisible armies for his help, and made the unbelievers' purpose abject. Most exalted is God's word, for God is all-mighty and all-wise.