Sahih Bukhari Volume 1, Book 10, Hadith 635

حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا شَيْبَانُ، عَنْ يَحْيَى، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَتَادَةَ، عَنْ أَبِيهِ، قَالَ بَيْنَمَا نَحْنُ نُصَلِّي مَعَ النَّبِيِّ صلى الله عليه وسلم إِذْ سَمِعَ جَلَبَةَ رِجَالٍ فَلَمَّا صَلَّى قَالَ ‏"‏ مَا شَأْنُكُمْ ‏"‏‏.‏ قَالُوا اسْتَعْجَلْنَا إِلَى الصَّلاَةِ‏.‏ قَالَ ‏"‏ فَلاَ تَفْعَلُوا، إِذَا أَتَيْتُمُ الصَّلاَةَ فَعَلَيْكُمْ بِالسَّكِينَةِ، فَمَا أَدْرَكْتُمْ فَصَلُّوا وَمَا فَاتَكُمْ فَأَتِمُّوا ‏"‏‏

Narrated By 'Abdullah bin Abi Qatada : My father said, "While we were praying with the Prophet he heard the noise of some people. After the prayer he said, 'What is the matter?' They replied 'We were hurrying for the prayer.' He said, 'Do not make haste for the prayer, and whenever you come for the prayer, you should come with calmness, and pray whatever you get (with the people) and complete the rest which you have missed."