Musnad Ahmad 33:1156

Khalaf ibn al-Walid narrated to us, Khalid narrated to us, from Humayd al-A'raj, from Muhammad ibn al-Munkadir, from Jabir ibn Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) came out to us while we were reciting the Quran, and among us were the non-Arab and the Bedouin. He said: "Listen." Then he said: "Recite, for all is good. And there will come a people who will straighten it [the recitation] as an arrow is straightened; they will seek its haste [reward in this world] and will not seek its delay [reward in the Hereafter]."