صحیح بخاری · Hadith 5288

Narrated `Aisha: (the wife of the Prophet) When believing women came to the Prophet as emigrants, he used to test them in accordance with the order of Allah. 'O you who believe! When believing women come to you as emigrants, examine them . . .' (60.10) So if anyone of those believing women accepted the above mentioned conditions, she accepted the conditions of faith. When they agreed on those conditions and confessed that with their tongues, Allah's Apostle would say to them, "Go, I have accepted your oath of allegiance (for Islam). By Allah, and hand of Allah's Apostle never touched the hand of any woman, but he only used to take their pledge of allegiance orally. By Allah, Allah's Apostle did not take the pledge of allegiance of the women except in accordance with what Allah had ordered him. When he accepted their pledge of allegiance he would say to them, "I have accepted your oath of allegiance."