Sunan an-Nasa'i, Book 11, Hadith 128 (In-Book)

It was narrated that Jabir bin Samurah said: "Some of the peole of Al-Khufah complained about Sa'd to 'Umar. They said: 'By Allah, he does not pray properly.' He said: 'I lead them in prayer as the Messenger of Allah did, and I do not deviate from that. I take my time in the first two rak'ahs and make the other two shorter.' He (Umar) said: 'That is what I thought about you.'"

أَخْبَرَنَا حَمَّادُ بْنُ إِسْمَاعِيلَ بْنِ إِبْرَاهِيمَ ابْنِ عُلَيَّةَ أَبُو الْحَسَنِ، قَالَ حَدَّثَنَا أَبِي، عَنْ دَاوُدَ الطَّائِيِّ، عَنْ عَبْدِ الْمَلِكِ بْنِ عُمَيْرٍ، عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ وَقَعَ نَاسٌ مِنْ أَهْلِ الْكُوفَةِ فِي سَعْدٍ عِنْدَ عُمَرَ فَقَالُوا وَاللَّهِ مَا يُحْسِنُ الصَّلاَةَ ‏.‏ فَقَالَ أَمَّا أَنَا فَأُصَلِّي بِهِمْ صَلاَةَ رَسُولِ اللَّهِ صلى الله عليه وسلم لاَ أَخْرِمُ عَنْهَا أَرْكُدُ فِي الأُولَيَيْنِ وَأَحْذِفُ فِي الأُخْرَيَيْنِ ‏.‏ قَالَ ذَاكَ الظَّنُّ بِكَ ‏.‏

sunnah.com