It is narrated from Sayyiduna Sahl bin Sa'd (may Allah be pleased with him): A drink was brought to the Prophet (peace and blessings be upon him); on his right was a boy and on his left were the elders. The Prophet (peace and blessings be upon him) drank from it, then said to the boy: "Shall I give it to the elders?" The boy said: "I will not give preference to anyone over myself in what is left over from you or what comes from you." So the Prophet (peace and blessings be upon him) gave it to him; he drank it and did not give it to the elders.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5984