I saw the Messenger of Allah ﷺ praying and a sound came from his breast like the rumbling of a mill owing to weeping. (Using translation from Abū Dāʾūd 904)

رَأَيْتُ رَسُولَ اللَّهِ ﷺ يُصَلِّي وَفِي صَدْرِهِ أَزِيزٌ كَأَزِيزِ الْمِرْجَلِ مِنَ الْبُكَاءِ