Invocation for someone you have spoken ill to

قَالَ النَّبِيُّ صلى الله عليه وسلم: ((اللَّهُمَّ فَأَيُّمَا مُؤْمِنٍ سَبَبْتُهُ فَاجْعَلْ ذَلِكَ لَهُ قُرْبَةً إِلَيْكَ يَوْمَ الْقِيَامَةِ)).

(O Allah, to any believer whom I have insulted, let that be cause to draw him near to You on the Day of Resurrection.)