Al-Kāfi

Hadith 1767
repentance
4ـ عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدِ بْنِ خَالِدٍ عَنْ أَبِيهِ عَنْ مُحَمَّدِ بْنِ سِنَانٍ عَنْ طَلْحَةَ بْنِ زَيْدٍ عَنْ أَبِي عَبْدِ الله (عَلَيهِ السَّلام) أَنَّ رَسُولَ الله (صَلَّى اللهُ عَلَيْهِ وآلِه) كَانَ لا يَقُومُ مِنْ مَجْلِسٍ وَإِنْ خَفَّ حَتَّى يَسْتَغْفِرَ الله عَزَّ وَجَلَّ خَمْساً وَعِشْرِينَ مَرَّةً.
4. A number of our people have narrated from Ahmad ibn Muhammad ibn Khalid from his father from Muhammad ibn Sinan from Talhah ibn Zayd from Abu ‘Abdillah (a.s.) who has said the following: “The Messenger of Allah would not leave a gathering - even a small one until - he would plea for protection (forgiveness) from Allah, the Most Majestic, the Most Holy, twenty-five times.”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī