18.Ibrāhīm ibn Abī al-Bilād narrated from his father, from Abū ʿAbdillāh who said,

“If Allah knew [human beings capable of using] anything less than ‘uff’ [against their parents], He would have forbidden it, and that is the smallest form of undutifulness. Another form of undutifulness is for a man to look at his parents with a stern [and angry] stare.”