Ma'arif al-Qur'an
Mufti Muhammad Shafiعُذْرًا أَوْ نُذْرًا ( to provide excuses [ for the believers ] or giving warnings (to disbelievers…77:6) This phrase is complement to verse [ 5]: فَالْمُلْقِيَاتِ ذِكْرًا then bring down the advice, [ 77:5] The 'advice' refers to the 'revelation' that came down upon the Prophets. Verse 6 says that it serves two purposes. In the case of the people of truth and believers, it persuades them to seek excuse from Allah for their shortcomings, and pray for forgiveness; and in the case of the people of falsehood and disbelievers, it contains a warning for them of Allah's torment, if they oppose His command.