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
tirmidhi:3902 – Aḥmad b. Manīʿ > Hushaym > ʿAlī b. Zayd b. Judʿān > al-Naḍr b. Anas > Zayd b. Arqam > Katab > Anas b. Mālik Yuʿazzīh Fīman Uṣīb from Ahlih And Banī from his uncle Yawm al-Ḥarrah Fakatab Ilayh Innī Ubashhiruk Bibushrá from Allāh Innī

"I give you glad tidings of good news from Allah. I heard the Messenger of Allah ﷺ say: 'O Allah forgive the Ansar and the children of the Ansar, and the children of their children."  

الترمذي:٣٩٠٢ – حَدَّثَنَا أَحْمَدُ بْنُ مَنِيعٍ قَالَ حَدَّثَنَا هُشَيْمٌ قَالَ أَخْبَرَنَا عَلِيُّ بْنُ زَيْدِ بْنِ جُدْعَانَ قَالَ حَدَّثَنَا النَّضْرُ بْنُ أَنَسٍ عَنْ زَيْدِ بْنِ أَرْقَمَ أَنَّهُ كَتَبَ إِلَى أَنَسِ بْنِ مَالِكٍ يُعَزِّيهِ فِيمَنْ أُصِيبَ مِنْ أَهْلِهِ وَبَنِي عَمِّهِ يَوْمَ الْحَرَّةِ فَكَتَبَ إِلَيْهِ إِنِّي أُبَشِّرُكَ بِبُشْرَى مِنَ اللَّهِ إِنِّي

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ اللَّهُمَّ اغْفِرْ لِلأَنْصَارِ وَلِذَرَارِيِّ الأَنْصَارِ وَلِذَرَارِيِّ ذَرَارِيِّهِمْ هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ وَقَدْ رَوَاهُ قَتَادَةُ عَنِ النَّضْرِ بْنِ أَنَسٍ عَنْ زَيْدِ بْنِ أَرْقَمَ  

See similar narrations below:

Collected by Ṭabarānī
tabarani:5103 – Mūsá b. Hārūn > Shujāʿ b. Makhlad > Hushaym > ʿAlī b. Zayd > al-Naḍr b. Anas > Zayd b. Arqam

[Machine] I heard the Messenger of Allah ﷺ saying: "O Allah, forgive the Ansar, their progeny, and the progeny of their progeny."  

الطبراني:٥١٠٣ – حَدَّثَنَا مُوسَى بْنُ هَارُونَ ثنا شُجَاعُ بْنُ مَخْلَدٍ ثنا هُشَيْمٌ عَنْ عَلِيِّ بْنِ زَيْدٍ ثنا النَّضْرُ بْنُ أَنَسٍ عَنْ زَيْدِ بْنِ أَرْقَمَ قَالَ

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «اللهُمَّ اغْفِرْ لِلْأَنْصَارِ وَلِذَرَارِيِّ الْأَنْصَارِ وَلِذَرَارِيِّ ذَرَارِيِّهِمْ»