Surah al-Saff is Medinan. (1)

In the Name of Allah, the Most Compassionate, Most Merciful.

“Whatever is in the heavens and whatever is on the earth glorifies Allah. And He is the Almighty, All-Wise. O believers! Why do you say what you do not do? How detestable it is in the sight of Allah that you say what you do not do!” (1–3)

Regarding His words, “Whatever is in the heavens and whatever is on the earth glorifies Allah. And He is the Almighty, All-Wise. O believers! Why do you say what you do not do?”, the commentators said: The believers said, “If we knew which deeds were most beloved to Allah, we would surely perform them and expend our wealth and our lives in their cause.” So Allah revealed: “Indeed, Allah loves those who fight in His cause in ranks.” They were then tested with this on the day of Uhud, but they turned back in flight. Thereupon Allah Most High revealed, “Why do you say what you do not do?” (2)

Muhammad ibn Ka'b said: When Allah Most High informed His Messenger, peace and blessings be upon him, of the reward of the martyrs of Badr, the Companions said, (3) “Should we encounter fighting thereafter, we shall exert our utmost in it.” Yet they fled on the day of Uhud, so Allah reproached them with this verse. (4)

Qatadah and al-Dahhak said: It was revealed concerning (5) fighting. A man would say that he had fought when he had not,