"[Remember, O Muhammad], when you were asking help of your Lord, and He answered you, 'I will reinforce you with a thousand from the angels, rank after rank.'" Meaning: following one another, according to the Tafsir of Qatadah. Mujahid read "murdafīn" (with a fatha on the dal), meaning that Allah caused the Muslims to be followed [by them], i.e., He reinforced them.
Muhammad [Ibn Abi Zamanin] said: "And whoever read it as 'murdifīn' (with a kasra on the dal), it is from the expression: 'I caused a man to follow/ride behind' (ardaftu), meaning: when you come after him. From this is the saying of the poet:
'When the Gemini follows (ardafat) the Pleiades, I would have suspicions regarding the kin of Fatimah.'"
﴿إِذْ تَسْتَغِيثُونَ رَبَّكُمْ فَاسْتَجَابَ لَكُمْ أَنِّي مُمِدكُمْ﴾ مُقَوِّيكُمْ ﴿بِأَلْفٍ مِنَ الْمَلائِكَةِ مُرْدِفِينَ﴾ يَعْنِي: مُتَتَابِعِينَ؛ فِي تَفْسِيرِ قَتَادَةَ، وَقَرَأَ مُجَاهِد (مُردفِينَ) بِفَتْحِ الدَّالِ؛ بِمَعْنَى: أَنَّ اللَّهَ أَرْدَفَ الْمُسْلِمِينَ؛ أَيْ: أَمَدَّهُمْ.
قَالَ محمدٌ: وَمن قَرَأَ (مُردفِينَ) بِكَسْرِ الدَّالِ، فَهُوَ مِنْ قَوْلِهِمْ: أَرْدَفْتُ الرَّجُلَ؛ إِذَا جِئْتَ بَعْدَهُ؛ وَمِنْهُ قْولُ الشَّاعِرِ:
(إِذَا الْجَوْزَاءُ أَرْدَفَتِ الثُّرَيَّا … ظَنَنْتُ بِآلِ فَاطِمَةَ الظنونا﴾
