To the people of Kufa when he marched from Medina to Basra
Nahj al-Balāgha|Volume 1|Book 2|Chapter 57
وَأنا [وَإِنِّي] أُذَكِّرُ اللَّهَ مَنْ بَلَغَهُ كِتَابِي هذَا لَمَّا نَفَرَ إِلَىَّ، فَإِنْ كُنْتُ مُحْسِناً أعَانَنِي، وَإِنْ كُنْتُ مُسِيئاً اسْتَعْتَبَنِي.
In any case, to whomsoever this letter of mine reaches, I appeal to him in the name of Allāh that he should come to me and if I am in the right he should help me; but if I am in the wrong then he should try to get me to the right according to his view.