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
nasai-kubra:8425 – Zakariyyā b. Yaḥyá > Muḥammad b. ʿAbd al-Raḥīm > Ibrāhīm > Maʿn > Mūsá b. Yaʿqūb > al-Muhājir b. Mismār > ʿĀʾishah b. Saʿd And ʿĀmir b. Saʿd > Saʿd

[Machine] The Messenger of Allah ﷺ addressed the people and said, "After me, O people, I am your guardian (Wali)." They said, "You speak the truth." Then he took the hand of Ali and raised it, and said, "This is my guardian (Wali), and the one who succeeds me and the leader of those who follow me. Allah is the ally of whoever supports him and the enemy of whoever opposes him."  

الكبرى للنسائي:٨٤٢٥ – أَخْبَرَنِي زَكَرِيَّا بْنُ يَحْيَى قَالَ حَدَّثَنِي مُحَمَّدُ بْنُ عَبْدِ الرَّحِيمِ قَالَ حَدَّثَنَا إِبْرَاهِيمُ قَالَ حَدَّثَنَا مَعْنٌ قَالَ حَدَّثَنِي مُوسَى بْنُ يَعْقُوبَ عَنِ الْمُهَاجِرِ بْنِ مِسْمَارٍ عَنْ عَائِشَةَ بِنْتِ سَعْدٍ وَعَامِرِ بْنِ سَعْدٍ عَنْ سَعْدٍ

أَنَّ رَسُولَ اللهِ ﷺ خَطَبَ النَّاسَ فَقَالَ «أَمَّا بَعْدُ أَيُّهَا النَّاسُ فَإِنِّي وَلِيُّكُمْ» قَالُوا صَدَقْتَ ثُمَّ أَخَذَ بِيَدِ عَلِيٍّ فَرَفَعَهَا ثُمَّ قَالَ «هَذَا وَلِيِّي وَالْمُؤَدِّي عَنِّي وَالِ اللهُ مَنْ وَالَاهُ وَعَادِ مَنْ عَادَاهُ»  

See similar narrations below:

Collected by Nasāʾī's Kubrá
nasai-kubra:8340 – Hilāl b. Bishr > Muḥammad b. Khālid / Ibn ʿAthmah > Mūsá b. Yaʿqūb > Muhājir b. Mismār > ʿĀʾishah b. Saʿd from my father

[Machine] I heard the Messenger of Allah, ﷺ , on the Day of Judgement, he took the hand of Ali and gave a sermon in which he praised and thanked Allah. Then he said, "O people, I am your guardian." They said, "You have spoken the truth, O Messenger of Allah." Then he took the hand of Ali and raised it and said, "This is my successor and the executor of my will. Indeed, Allah is the protector of whoever supports him and the enemy of whoever opposes him."  

الكبرى للنسائي:٨٣٤٠ – أَخْبَرَنِي هِلَالُ بْنُ بِشْرٍ قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ خَالِدٍ وَهُوَ ابْنُ عَثْمَةَ قَالَ حَدَّثَنَا مُوسَى بْنُ يَعْقُوبَ قَالَ حَدَّثَنِي مُهَاجِرُ بْنُ مِسْمَارٍ عَنْ عَائِشَةَ بِنْتِ سَعْدٍ قَالَتْ سَمِعْتُ أَبِي يَقُولُ

سَمِعْتُ رَسُولَ اللهِ ﷺ يَوْمَ الْجُحْفَةِ وَأَخَذَ بِيَدِ عَلِيٍّ فَخَطَبَ فَحَمِدَ اللهَ وَأَثْنَى عَلَيْهِ ثُمَّ قَالَ يَا أَيُّهَا النَّاسُ «إِنِّي وَلِيُّكُمْ» قَالُوا صَدَقْتَ يَا رَسُولَ اللهِ ثُمَّ أَخَذَ بِيَدِ عَلِيٍّ فَرَفَعَهَا وَقَالَ «هَذَا وَلِيِّي والْمُؤَدِّي عَنِّي وَإِنَّ اللهَ مُوَالِ مَنْ وَالَاهُ وَمُعَادٍ مَنْ عَادَاهُ»