Bukhari

Hadith Commentary:
From this hadith, it is understood that when taking the pledge (bay‘ah) from women, it is sufficient to do so verbally; it is not permissible to touch their hands. This is contrary to what some ignorant spiritual guides (pirs) of our time do. May Allah bring them to understanding and guide them.
The Treaty of Hudaybiyyah was concluded with well-known conditions, some of which were apparently disagreeable to the Muslims. Nevertheless, the agreement was written according to those very conditions. This proves that in such circumstances, both parties may stipulate appropriate conditions.

Hadith Commentary:
(1)
Hafiz Ibn Hajar rahimahullah states:
Under this heading, both permissible and impermissible types of conditions are discussed. For example:
At the time of accepting Islam, a disbeliever may stipulate a condition that he should not be transferred from one city to another—this is permissible. However, it is impermissible for him to stipulate that he will not perform prayer or will not pay zakat.
(Fath al-Bari: 5/384)
Imam Bukhari rahimahullah most likely intends to establish that any condition which is contrary to the Shari‘ah will be rejected, and acting upon it will not be permissible, whereas those conditions which are in accordance with the Shari‘ah must be fulfilled.
According to the agreement, women were included in the conditions, but Allah Himself declared their return to be invalid, because returning the women could become a cause of tribulation (fitnah).
Men have the courage to escape and flee from their captors, but women do not possess such courage.
Since returning the women was contrary to the Shari‘ah, Allah Himself intervened and prevented the Messenger of Allah sallallahu alayhi wa sallam from doing so.
In this, neither did the Messenger of Allah sallallahu alayhi wa sallam violate the agreement, nor did the disbelievers object to it; rather, they too accepted this divine command.
Had there been opposition, fighting would have ensued.
The battles had already broken their backs.

(2)
In this, there is mention of the pledge (bay‘ah): that when taking the pledge from women, one should not shake hands or the like.
The conditions by which the believing women were tested are mentioned in the following verse:
﴿يَا أَيُّهَا النَّبِيُّ إِذَا جَاءَكَ الْمُؤْمِنَاتُ يُبَايِعْنَكَ عَلَىٰ أَن لَّا يُشْرِكْنَ بِاللَّـهِ شَيْئًا وَلَا يَسْرِقْنَ وَلَا يَزْنِينَ وَلَا يَقْتُلْنَ أَوْلَادَهُنَّ وَلَا يَأْتِينَ بِبُهْتَانٍ يَفْتَرِينَهُ بَيْنَ أَيْدِيهِنَّ وَأَرْجُلِهِنَّ وَلَا يَعْصِينَكَ فِي مَعْرُوفٍ ۙ فَبَايِعْهُنَّ وَاسْتَغْفِرْ لَهُنَّ اللَّـهَ ۖ إِنَّ اللَّـهَ غَفُورٌ رَّحِيمٌ ﴿١٢﴾)
“O Prophet! When believing women come to you to give you the pledge that they will not associate anything with Allah, nor will they steal, nor will they commit adultery, nor will they kill their children, nor will they bring any falsehood which they have invented between their hands and feet, nor will they disobey you in what is right—then accept their pledge and ask Allah to forgive them. Surely, Allah is Most Forgiving, Most Merciful.”
(al-Mumtahanah: 60:12)
With the six conditions mentioned in this noble verse, the women would be tested.
If they were believers, they would acknowledge and affirm these six things, and if they were not believers, they would deny them.