The Prophet ﷺ said: Those who do not show mercy to our young ones and do not realise the right of our elders are not from us. (Using translation from Abū Dāʾūd 4943)
أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ «مَنْ لَمْ يَرْحَمْ صَغِيرَنَا وَيَعْرِفْ حَقَّ كَبِيرِنَا فَلَيْسَ مِنَّا»