Mishkat al-Masabih
Mishkat al-Masabih 359
How to act when relieving oneself - Section 2
Arabic hadith text
وَعَنْ عَائِشَةَ قَالَتْ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا خَرَجَ مِنَ الْخَلَاءِ قَالَ «غفرانك» . رَوَاهُ التِّرْمِذِيّ وَابْن مَاجَه والدارمي
Translation
‘A'isha told that when the Prophet came out from the privy he said, "Grant Thy forgiveness.” Tirmidhi, Ibn Majah and Darimi transmitted it.