If you want salvation and to be saved from the torture of Allah, then look at and consider the old-aged Muslims as your own father, and the middle-aged one as your brother, and the youngest of them as your son.  Thus, you should revere well your own father, be generous to your own brother, and be tender and compassionate to your own son.

—Mohammad bin Ka’ab to ‘Umar b. ‘Abd al-‘Azīz

(Read on pg 16, Al-Hafiz Jamaludeen Abi Al-Faraj and Abd Ar-Rahman bin Al-Jawzi and Al-Qurashi and Al-Baghdadi, The Biography and virtues of Omar bin Abd Al-Aziz: The Ascetic Caliph. Dar Al-Kotob Al-ilmiyah. Beirut:2001.)