Musnad Ahmad 1510

Bahz said: I heard Jabir bin Samurah say: ‘Umar (رضي الله عنه) said to Saʼd (رضي الله عنه): “You are causing people to complain about you in everything, even your prayer.” He said: “As far as I am concerned, this is what I do: I make the first two rak"ahs long and l make the last two rak"ahs brief. I do my best to follow the example of the Messenger of Allah (ﷺ) in my prayer.” "Umar said: “That is what one would think of you - or -That is what I thought of you.”