Sahih Muslim Book 8, Hadith Number 3314.

Chapter: It is permissible to caste a glance at the face and the palms of a woman who one intends to marry.

Abu Huraira (Allah be pleased with him) reported: I was in the company of Allah’s Messenger (way peace be upon him) when there came a man and informed him that he had contracted to marry a woman of the Ansar. Thereupon Allah’s Messenger (May peace be upon him) said: Did you cast a glance at her? He said: No. He said: Go and cast a glance at her, for there is something in the eyes of the Ansar.