Praise be to Allah,
Muhammad ibn Abu Adiyy narrated to us from Humayd [at-Taweel] from Anas ibn Maalik who said,
“One night, the Messenger of Allah was offering [nocturnal voluntary] prayers just outside [(Aa’ishah’s] apartment in the mosque when some people came and prayed behind him, so he made the prayer brief and went into the apartment. Then he came out and did the same thing several times, and each time people would pray behind him. The next morning people asked him, ‘Messenger of Allah, you prayed [and we prayed behind you] and we would like you to make your prayer a bit longer.’ He said, ‘I knew you were there so I deliberately made it brief.”‘
(Musnad Ahmad, Vol. 3, p. 103. 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)