Sahih Bukhari | Volume 9 | Hadith Number 321

Narrated by 'Aisha
The Prophet used to take the Pledge of allegiance from the women by words only after reciting this Holy Verse: (60:12) "...that they will not associate anything in worship with Allah." (60:12) And the hand of Allah's Apostle did not touch any woman's hand except the hand of that woman his right hand possessed. (i.e. his captives or his lady slaves).