Musnad Ahmad 30:2387

Isma'il narrated to us, Hisham informed us, from Muhammad ibn Sirin, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When the call to prayer (iqamah) is made, none of you should hasten toward it. Rather, let him walk, and upon him should be tranquility and dignity. Pray what you catch, and complete what you missed."