Musannaf Ibn Abi Shayba 3:5024

Waki' narrated to us, he said: Sufyan narrated to us, from Sa'd ibn Ibrahim, from 'Umar ibn Abi Salamah, from Abu Hurayrah, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "When you come to the prayer, come to it with dignity and tranquility. Whatever you catch, pray, and whatever you miss, complete it."