Is the saying attributed to Omar ibn al-Khattab to Sa’d ibn Abi Waqqas on the Day of Qadisiyyah, “O Sa’d, know that the sins of the army are more fearsome to it than its enemy, and that we prevail over our enemy through our obedience to Allah and our enemy’s disobedience to Him. So, if we become equal in disobedience, our enemy will have the upper hand, by numbers and equipment,” authentic? And in which book was it mentioned? And can a Muslim and a disbeliever be equal in disobedience, even if the disbeliever is a disbeliever and the Muslim is a Muslim?

The text indicates that the attributed statement of Umar ibn al-Khattab, regarding his advice to Sa'd ibn Abi Waqqas to fear Allah and avoid sins as a source of strength in war, is not authentically ascribed to him. Rather, Ibn Abd Rabbih mentioned it without a chain of narration (isnad). A similar meaning was reported from Umar ibn Abd al-Aziz with a weak isnad, and also from Umar ibn al-Khattab concerning the conquest of Egypt, but with a very weak and differently worded isnad.

It is not correct that a Muslim and a disbeliever are equal in their standing before Allah. A believer, even if they commit sins, will not remain eternally in Hellfire, whereas a disbeliever will. The Holy Quran states that the blind and the seeing are not equal, and that "those who believe and do righteous deeds are not like the evildoers." Believers who are punished in the Fire due to their sins will eventually be brought out through the intercession of angels and prophets, which clearly demonstrates the difference between a Muslim and a disbeliever.

The weakness of these narrations does not mean that disobedience does not affect the weakness and defeat of the Ummah. Allah Almighty said regarding the Battle of Uhud: "And when a disaster struck you, although you had inflicted twice as much, you said, 'How has this happened?' Say, 'It is from yourselves.'" Sins contribute to the enemies gaining dominance, and victory comes through sincere intentions and worship, not through numbers or equipment. The Ummah is granted victory through its weak, their supplications, and their sincerity to Allah.