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
bayhaqi:643 – Abū ʿAbdullāh al-Ḥāfiẓ And ʾAbū Saʿīd b. Abū ʿAmr > Abū al-ʿAbbās Muḥammad b. Yaʿqūb > Hārūn b. Sulaymān > ʿAbd al-Raḥman b. Mahdī > ʿUmar b. Abū Wahb > Jamīl al-ʿIjlī > Abū Wahb al-Khuzāʿī > Abū Hurayrah

[Machine] Whoever touches their private parts should perform ablution, and if they only touch them from the outside of their clothing, then wudu is not required for them.  

البيهقي:٦٤٣ – أَخْبَرَنَاهُ أَبُو عَبْدِ اللهِ الْحَافِظُ وَأَبُو سَعِيدِ بْنُ أَبِي عَمْرٍو قَالَا ثنا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ ثنا هَارُونُ بْنُ سُلَيْمَانَ ثنا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ عَنْ عُمَرَ بْنِ أَبِي وَهْبٍ عَنْ جَمِيلٍ الْعِجْلِيِّ عَنْ أَبِي وَهْبٍ الْخُزَاعِيِّ عَنْ أَبِي هُرَيْرَةَ قَالَ

مَنْ مَسَّ فَرْجَهُ فَلْيَتَوَضَّأْ وَمَنْ مَسَّهُ يَعْنِي مِنْ وَرَاءِ الثَّوْبِ فَلَيْسَ عَلَيْهِ وُضُوءٌ  

See similar narrations below:

Collected by Ṭabarānī
tabarani:5221 – ʿUbayd b. Ghannām > Abū Bakr b. Abū Shaybah > ʿAbd al-Aʿlá > Muḥammad b. Isḥāq > al-Zuhrī > ʿUrwah > Zayd b. Khālid al-Juhanī

[Machine] The Prophet ﷺ said, "Whoever touches his private parts should perform ablution."  

الطبراني:٥٢٢١ – حَدَّثَنَا عُبَيْدُ بْنُ غَنَّامٍ ثنا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ثنا عَبْدُ الْأَعْلَى عَنْ مُحَمَّدِ بْنِ إِسْحَاقَ عَنِ الزُّهْرِيِّ عَنْ عُرْوَةَ عَنْ زَيْدِ بْنِ خَالِدٍ الْجُهَنِيِّ

عَنِ النَّبِيِّ ﷺ قَالَ «مَنْ مَسَّ فَرْجَهُ فَلْيَتَوَضَّأْ»