Nahj al-Balāgha
Hadith 560يَا أَحْنَفُ، كَأَنِّي بِهِ وَقَدْ سَارَ بِالْجَيْشِ الَّذِي لاَ يَكُونُ لَهُ غُبَارٌ وَلاَ لَجَبٌ، وَلاَ قَعْقَعَةُ لُجُم، وَلاَ حَمْحَمَةُ خَيْل، يُثِيرُونَ الاْرْضَ بِأَقْدَامِهِمْ كَأَنَّهَا أَقْدَامُ النَّعَامِ.
O Aḥnaf! It is as though I see him advancing with an army which has neither dust nor noise, nor rustling of reins, nor neighing of horses. They are trampling the ground with their feet as if they are the feet of ostriches.