Praise be to Allah,
[Muhammad] ibn Abu Adiyy and Yazeed [ibn Haaroon] narrated to us from Humayd [at-Taweel] from Anas ibn Maalik who said,
“I was playing with some boys and the Messenger of Allah (PBUH) came to us. (Yazeed added in his narration, ‘and he greeted us with salaam salutations.’) He then took me by the hand, sent me on an errand, and sat down in the shade of a wall until I came back to him, and I conveyed the message with which he had sent me. When I returned to [tny mother] Umm Sulaym, she asked me, ‘What kept you?’ I said, ‘Allah’s sent me on an errand.’ She asked, ‘What was it?’ I said, ‘It’s a secret. ‘ She said, ‘Keep the secret of the Messenger of Allah (PBUH).’ And I never told anyone about it after that.”
(Musnad Ahmad, Vol. 3, p. 109. The isnaad of this hadeeth is Saheeh according to the conditions set by al-Bukhaaree and Muslim.)
Source:
Thulaathiyyaat Musnad Ahmad ibn Hanbal (may Allah have mercy on him)
Reports of Imaam Ahmad that have only three narrators between him and the Prophet, peace, and blessings be upon him.
Shaykh Muhammad ibn Ahmad ibn Saalim as–Saffaareenee al–Hanbalee ~(1114 –1188 AH)