مُسْنَدُ أَحْمَدَ
Musnad Ahmad 4004
Musnad of Abdullah bin Mas'ood
It was narrated that Abdur-Rahman bin al-Aswad said: ‘Alqamah and al-Aswad asked permission to enter upon ‘Abdullah. He said: There will come to you rulers who will be distracted from the time of prayer, so offer the prayer at the proper time. Then he got up and prayed (standing) between me and him (leading us in prayer), then he said: This is what I saw The Messenger of Allah (ﷺ) do.
Musnad Ahmad 4030Its isnad is qawi]