Ar-Rabi, the daughter of An-Nadr broke the tooth of a girl, and the relatives of Ar-Rabi` requested the girl's relatives to accept the Irsh (compensation for wounds etc.) and forgive (the offender), but they refused. So, they went to the Prophet (ﷺ) who ordered them to bring about retaliation. Anas bin An-Nadr asked, "O Allah"; Apostle! Will the tooth of Ar-Rabi` be broken? No, by Him Who has sent you with the Truth, her tooth will not be broken." The Prophet (ﷺ) said, "O Anas! Allah"; law ordains retaliation." Later the relatives of the girl agreed and forgave her. The Prophet (ﷺ) said, "There are some of Allah's slaves who, if they take an oath by Allah, are responded to by Allah i.e. their oath is fulfilled). Anas added, "The people agreed and accepted the Irsh."
Sahih al-Bukhari Book 53, Hadith 13
← Previous Hadith `Abdullah bin Sahl and Muhaiyisa bin Mas`ud bin Zaid went to Khaibar when it had a peace treaty (with the Muslims).

Sahih al-Bukhari Book 53, Hadith 12 Next Hadith → By Allah, Al-Hasan bin `Ali led large battalions like mountains against Muawiya. `Amr bin Al-As said (to Muawiya), "I surely see battalions which will not turn back before killing their opponents." Muawiya who was really the best of the two men said to him, "O `Amr! If these killed those and those killed these, who would be left with me for the jobs of the public, who would be left with me for their women, who would be left with me for their children?" Then Muawiya sent two Quraishi men from the tribe of `Abd-i-Shams called `Abdur Rahman bin Sumura and `Abdullah bin 'Amir bin Kuraiz to Al-Hasan saying to them, "Go to this man (i.e. Al-Hasan) and negotiate peace with him and talk and appeal to him." So, they went to Al-Hasan and talked and appealed to him to accept peace. Al-Hasan said, "We, the offspring of `Abdul Muttalib, have got wealth and people have indulged in killing and corruption (and money only will appease them)." They said to Al-Hasan, "Muawiya offers you so and so, and appeals to you and entreats you to accept peace." Al-Hasan said to them, "But who will be responsible for what you have said?" They said, "We will be responsible for it." So, whatever Al- Hasan asked they said, "We will be responsible for it for you." So, Al-Hasan concluded a peace treaty with Muawiya. Al-Hasan (Al-Basri) said: I heard Abu Bakr saying, "I saw Allah's Messenger (ﷺ) on the pulpit and Al-Hasan bin `Ali was by his side. The Prophet (ﷺ) was looking once at the people and once at Al-Hasan bin `Ali saying, 'This son of mine is a Saiyid (i.e. a noble) and may Allah make peace between two big groups of Muslims through him."

Sahih al-Bukhari Book 53, Hadith 14