Sahih Muslim Book - 4, Hadith - 1016

حَدَّثَنَا يَحْيَى بْنُ يَحْيَى أَخْبَرَنَا هُشَيْمٌ عَنْ عَبْدِ الْمَلِكِ بْنِ عُمَيْرٍ عَنْ جَابِرِ بْنِ سَمُرَةَ أَنَّ أَهْلَ الْكُوفَةِ شَكَوْا سَعْدًا إِلَى عُمَرَ بْنِ الْخَطَّابِ فَذَكَرُوا مِنْ صَلَاتِهِ فَأَرْسَلَ إِلَيْهِ عُمَرُ فَقَدِمَ عَلَيْهِ فَذَكَرَ لَهُ مَا عَابُوهُ بِهِ مِنْ أَمْرِ الصَّلَاةِ فَقَالَ إِنِّي لَأُصَلِّي بِهِمْ صَلَاةَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَا أَخْرِمُ عَنْهَا إِنِّي لَأَرْكُدُ بِهِمْ فِي الْأُولَيَيْنِ وَأَحْذِفُ فِي الْأُخْرَيَيْنِ فَقَالَ ذَاكَ الظَّنُّ بِكَ أَبَا إِسْحَقَ.

It was narrated from Jabir bin Samurah that the people of Al-Kufah complained about Sa'd to 'Umar bin Al-Khattab, and they complained about his prayer. 'Umar sent for him and he came. He told him how they had found fault with his prayer. He said: "I lead them in prayer according to the prayer of the Messenger of Allah (s.a.w) and I do no more and no less than that. I make first two Rak'ah long, and I make the last two short." He said: "That is what I thought of you, Abu Ishaq."