Sahih Muslim 1866 a
It has been narrated on the authority of 'A'isha, the wife of the Prophet (ﷺ). She said:
When the believing women migrated (to Medina) and came to the Messenger of Allah (ﷺ), they would be tested in accordance with the following words of Allah. the Almighty and Exalted:" O Prophet, when believing women come to thee to take the oath of fealty to thee that they will not associate in worship anything with God, that they will not steal. that, they will not commit adultery..." to the end of the verse (lx. 62). 
Whoso from the believing women accepted these conditions and agreed to abide by them were considered to have offered themselves for swearing fealty. When they had (formally) declared their resolve to do so, the Messenger of Allah (may peace he upon him) would say to them: You may go. I have confirmed your fealty. By God, the hand of the Messenger of Allah (ﷺ) never touched the hand of a woman. He would take the oath of fealty from them by oral declaration. By God, the Messenger of Allah (ﷺ) never took any vow from women except that which God had ordered him to take, and his palm never touched the palm of a woman. When he had taken their vow, he would tell them that he had taken the oath from them orally.
حَدَّثَنِي أَبُو الطَّاهِرِ، أَحْمَدُ بْنُ عَمْرِو بْنِ سَرْحٍ أَخْبَرَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ، بْنُ يَزِيدَ قَالَ قَالَ ابْنُ شِهَابٍ أَخْبَرَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم قَالَتْ كَانَتِ الْمُؤْمِنَاتُ إِذَا هَاجَرْنَ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم يُمْتَحَنَّ بِقَوْلِ اللَّهِ عَزَّ وَجَلَّ ‏{‏ يَا أَيُّهَا النَّبِيُّ إِذَا جَاءَكَ الْمُؤْمِنَاتُ يُبَايِعْنَكَ عَلَى أَنْ لاَ يُشْرِكْنَ بِاللَّهِ شَيْئًا وَلاَ يَسْرِقْنَ وَلاَ يَزْنِينَ‏}‏ إِلَى آخِرِ الآيَةِ ‏.‏ قَالَتْ عَائِشَةُ فَمَنْ أَقَرَّ بِهَذَا مِنَ الْمُؤْمِنَاتِ فَقَدْ أَقَرَّ بِالْمِحْنَةِ وَكَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا أَقْرَرْنَ بِذَلِكَ مِنْ قَوْلِهِنَّ قَالَ لَهُنَّ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ انْطَلِقْنَ فَقَدْ بَايَعْتُكُنَّ ‏"‏ ‏.‏ وَلاَ وَاللَّهِ مَا مَسَّتْ يَدُ رَسُولِ اللَّهِ صلى الله عليه وسلم يَدَ امْرَأَةٍ قَطُّ ‏.‏ غَيْرَ أَنَّهُ يُبَايِعُهُنَّ بِالْكَلاَمِ - قَالَتْ عَائِشَةُ - وَاللَّهِ مَا أَخَذَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَلَى النِّسَاءِ قَطُّ إِلاَّ بِمَا أَمَرَهُ اللَّهُ تَعَالَى وَمَا مَسَّتْ كَفُّ رَسُولِ اللَّهِ صلى الله عليه وسلم كَفَّ امْرَأَةٍ قَطُّ وَكَانَ يَقُولُ لَهُنَّ إِذَا أَخَذَ عَلَيْهِنَّ ‏"‏ قَدْ بَايَعْتُكُنَّ ‏"‏ ‏.‏ كَلاَمًا ‏.‏