Hadith 2:70
Hudhaifa said, “ If you Qur'an readers follow a straight course you will have attained great precedence; but if you go right and left you will have fallen into vast error.” Bukhari transmitted it.
وَعَن حُذَيْفَة قَالَ: يَا مَعْشَرَ الْقُرَّاءِ اسْتَقِيمُوا فَقَدْ سَبَقْتُمْ سَبْقًا بَعِيدًا وَإِنْ أُخِذْتُمْ يَمِينًا وَشِمَالًا لَقَدْ ضللتم ضلالا بَعيدا. رَوَاهُ البُخَارِيّ
Original Reference: Mishkat al-Masabih 274