Language:
كتاب النكاح
67  
Wedlock, Marriage (Nikaah)
(48)
Chapter: Al-Khutba (for Nikah)
(47)
باب الْخُطْبَةِ
Sahih al-Bukhari 5146

Narrated Ibn `Umar:

Two men came from the east and delivered speeches, and the Prophet (ﷺ) said, "Some eloquent speech has the influence 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)

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 لَسِحْرً‏"‏‏.‏
Reference : Sahih al-Bukhari 5146
In-book reference : Book 67, Hadith 81
USC-MSA web (English) reference : Vol. 7, Book 62, Hadith 76
  (deprecated numbering scheme)