It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "He is not one of us who does not show mercy to our young and does not recognise the right (and rank) of our elders." This hadith is sahih (authentic) on the condition of Muslim, because he used Abdullah bin Amir al-Yahsubi as evidence, but the two Shaykhs did not record it. Its supporting report (shahid) is the well-known hadith which Muhammad bin Ishaq and others narrated from Amr bin Shu'ayb, from his father, from his grandfather. In the hadith of Ikrimah from Sayyiduna Ibn Abbas (may Allah be pleased with them both) there are also the words: "and he enjoins what is right and forbids what is wrong", but I have left it out here because its narrator is Layth bin Abi Sulaym (who is weak).