Dua 242 ☆
اللَّهُمَّ فَأَيُّمَا مُؤْمِنٍ سَبَبْتُهُ فَاجْعَلْ ذَلِكَ لَهُ قُرْبَةً إِلَيْكَ يَوْمَ الْقِيَامَةِ
Allaahumma fa'ayyumaa mu'minin sababtuhu faj'al thaalika lahu qurbatan 'ilayka yawmal-qiyaamati.
O Allah, whomever of the believers I have abused, give him the reward of a sacrificial slaughter for it on the Day of Resurrection.
Reference: Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 11/171, Muslim 4/2007. The wording in Muslim's report is: 'make it a purification for him and a source of mercy.