Holding Fast to the Qur'an and Sunnah

Bukhari :: Book 9 :: Volume 92 :: Hadith 465

Narrated 'Abdullah Al Muzam:

The Prophet said, "Perform (an optional) prayer before Maghrib prayer." (He repeated it thrice) and the third time he said, "Whoever wants to offer it can do so," lest the people should take it as a Sunna (tradition). (See Hadith No. 277, Vol. 2)