Musnad Ahmad 30:3210

Muhammad ibn Ja'far narrated to us, he said: Sa'id and 'Abd al-Wahhab narrated to us, from Sa'id—the meaning [of the narration]—from Qatadah, from Abu Rafi', from Abu Hurayrah, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "When the prayer is called, walk to it, and upon you be tranquility and dignity. So whatever you catch, pray it, and whatever you miss, complete it."