Ma'mar narrated from Az-Zuhri, from Urwah that Aishah said:
"The Messenger of Allah would not have examined (the women) except for the Ayah in which Allah said: When believing come to you pledging to you." Ma'mar said: "Ibn Tawus informed me from his father who said: 'The hand of the Messenger of Allah did not touch the hand of a women he had not acquired.'"
English reference: Vol. 5, Book 44, Hadith 3306
Arabic reference: Book 47, Hadith 3620