Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Bukhari :: Book 5 :: Volume 59 :: Hadith 704

Narrated Ibn Umar:

Allah's Apostle said to his companions who were at Al-Hijr, "Do not enter upon these people who are being punished, except in a weeping state, lest the same calamity as of theirs should befall you..."