Sahih Bukhari Volume 7, Book 67, Hadith 5148

حَدَّثَنَا قَبِيصَةُ، حَدَّثَنَا سُفْيَانُ، عَنْ زَيْدِ بْنِ أَسْلَمَ، قَالَ سَمِعْتُ ابْنَ عُمَرَ، يَقُولُ جَاءَ رَجُلاَنِ مِنَ الْمَشْرِقِ فَخَطَبَا فَقَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ إِنَّ مِنَ الْبَيَانِ لَسِحْرًا ‏"‏‏

Narrated By Ibn 'Umar : Two men came from the east and delivered speeches, and the Prophet said, "Some eloquent speech has the in fluency of magic (e.g., some people refuse to do something and then a good eloquent speaker addresses them and then they agree to do that very thing after his speech)."