In response to a letter from Muawiya
Nahj al-Balāgha|Volume 1|Book 2|Chapter 17
وَأَمَّا قَوْلُكَ: إِنَّ الْحَرْبَ قَدْ أَكَلَتِ الْعَرَبَ إِلَّا حُشَاشَاتِ أَنْفُس بَقِيَتْ، أَلَا وَمَنْ أَكَلَهُ الْحَقُّ فَإِلَى الْجَنَّةِ، وَمَنْ أَكَلَهُ الْبَاطِلُ فَإِلَى النّارِ.
As regards your saying that the war has eaten up Arabia save its last breath, you should know that he whom right has eaten up goes to Paradise and he whom wrong has eaten up goes to Hell.