What is meccan pledge?
Following the zuhr salat, the Blessed Prophet -upon him blessings and peace- ascended the Safa Hill to accept the Meccans’ pledge of allegiance. It was first the Qurayshi men to offer their pledge ‘on Islam and jihad’. The women followed them. Regarding the pledge of women, Allah, glory unto Him, had already pronounced:
“O Prophet! When believing women come to you, giving you a pledge that they will not ascribe nothing as a partner unto Allah, and will not steal, and will not commit fornication, and will not kill their children, and will not produce any lie that they have forged of themselves, and will not disobey you in what is good, accept their pledge and ask forgiveness for them from Allah. Surely Allah is Forgiving, Merciful.” (al-Mumtahinah, 12)
Women offered their pledge by dipping their hands in a small pot of water in which the Blessed Prophet -upon him blessings and peace- had dipped his own hands. There was never a case where the Prophet -upon him blessings and peace- accepted the pledge of women by shaking their hands.
Umaymah bint Ruqayqah -Allah be well-pleased with her- explains:
“When, as a group of Ansari women, we went to the Messenger of Allah and said, ‘We give our pledge to you that we will not ascribe nothing as a partner unto Allah, we will not steal, we will not commit fornication, we will not kill our children, we will not forge any lies and we will obey you in your legitimate commands’, he replied, ‘Only in matters within your power and with what you can cope…’
Hearing these considerate words, we thought, ‘Allah and His Messenger are more compassionate towards us than we are towards ourselves…so let’s give our pledge!’
The women wanted to shake his hands but the Messenger of Allah said, ‘I do not shake hands with women. A word I say to a hundred women counts as if I have said to each of them separately.’” (Muwatta’, Bayat, 2; Tirmidhi, Siyar, 37/1597)
 Ahmad, III, 415; Bukhari, Maghazi, 53.
Source: Osman Nuri Topbaş, The Prophet Muhammed Mustafa the Elect II, Erkam Publications