on the authority of jabir, who said: "when we started to pay allegiance to the prophet [pbuh], as‘ad bin zurarah stood up and gave the following short address: "take it easy people of yathrib! we have not covered that long distance except because we have had deep belief that he (muhammad [pbuh]) is the messenger of allâh. we are already convinced that following him entails departure from the pagan arabs even if it were at the risk of our life. should you preserve in this course, holdfast to it, and your great reward is placed in the hand of allâh, but if you are caught in fear, i admonish you to give it up just now, and then you would be more excusable by allâh." [musnad ahmad]

with respect to the two women, the pledge was taken orally for the prophet [pbuh] had never shaken hands with a strange lady. [muslim 2/131]