Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
quran:8:9 –

˹Remember˺ when you asked help of your Lord, and He answered you, "Indeed, I will reinforce you with a thousand from the angels, following one another."  

When you sought help from your Lord, asking Him to help you by granting you victory over them, and He answered you ˹saying˺: ‘I shall reinforce you, I shall assist you, with a thousand angels, rank upon rank’, one rank following after the next: God promised them this ˹number˺ at first, but it then became three thousand, and then five thousand, as stated in ˹sūrat˺ Āl ‘Imrān ˹Q. 3:124-125˺ (a variant reading ˹of alf, ‘thousand’˺ has the plural āluf, ‘thousands’, similar ˹in pattern˺ to aflus, ‘coins’).
القرآن:٨:٩ –

إِذْ تَسْتَغِيثُونَ رَبَّكُمْ فَاسْتَجَابَ لَكُمْ أَنِّي مُمِدُّكُمْ بِأَلْفٍ مِنَ الْمَلَائِكَةِ مُرْدِفِينَ  

اذكر {إذ تستغيثون ربَّكم} تطلبون منه الغوث بالنصر عليهم {فاستجاب لكم أني} أي بأني {مُمدُّكم} معينكم {بألف من الملائكة مردفين} متتابعين يردف بعضهم بعضا وعدهم بها أوَّلا ثم صارت ثلاثة آلاف ثم خمسة كما في آل عمران وقرئ بآلُف كأفُلس جمع.