Assalamu Alaikum, According to a hadith in bukhari, Prophet (pbuh) forgave the jewish woman who poisoned him and he did not kill her. I read elsewhere that the Prophet (pbuh) killed poetesses who slandered him after the conquest of Mecca. Why didn't he forgive them as he forgave people who insulted and threw stones on him in Taif?. Also I read that many muslim scholars are agreed that a person who slanders the prophet(pbuh) should be killed. If punishment for insulting the prophet is death, why did he forgive that jewish woman and people who insulted him in Taif?.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Firstly, you should know that there is no harm if the Muslim individual asks about something to know his religion better and understand it properly; however, one should avoid questions that indicate objection (to Sharee'ah).

Secondly, there is no agreement among scholars that the woman who had tried to poison the Prophet, sallallaahu ‘alayhi wa sallam, (i.e. who had poisoned the mutton to him) was not executed. Al-Haafith Ibn Hajar reported in Al-Isaabah fi Tamyeez As-Sahaabah from Ma‘amar from Az-Zuhri that "she converted to Islam and thus the Prophet, sallallaahu ‘alayhi wa sallam, pardoned her. Some others reported that he, sallallaahu ‘alayhi wa sallam, executed her. A third group said that he, sallallaahu ‘alayhi wa sallam, executed her as a Qisaas (i.e. equitable retribution) for Bishr ibn Al-Baraa' who ate from that mutton and then died. This is the correct opinion. As for he, sallallaahu ‘alayhi wa sallam, pardoning her for his legal right on her and not executing her as a Qisaas (for the harm she did to him), then it is his right to do so."

Al-Haafith Ibn Hajar in Fat-h Al-Baari, reporting quoted As-Suhayli as saying: "He, sallallaahu ‘alayhi wa sallam, pardoned her for he never took revenge for himself; however, he executed her as a Qisaas for Bishr. I said: It is possible that he pardoned her because she embraced Islam, however, he postponed executing her until Bishr died; as by his death Qasaas became obligatory when its condition was fulfilled." [End quote]

Thirdly, when he, sallallaahu ‘alayhi wa sallam, pardoned the people of At-Taa'if, this was at the beginning of Islam. At that time, he, sallallaahu ‘alayhi wa sallam, was ordered to pardon and forgive those who did wrong to him as Allaah The Almighty Says (what means): {So turn aside from them and say, "Peace." But they are going to know.}[Quran 43: 89]

Moreover, he hoped that those people may embrace Islam or have children who would embrace Islam. ‘Aa’ishah narrated that the Prophet, sallallaahu ‘alayhi wa sallam, said: "The Angel of the Mountains called me and greeted me, then said: ‘ O Muhammad, Allaah has heard what your people have said to you, and I am the Angel of the Mountains and your Lord has sent me to you so that you may give me your orders. What do you want? If you wish I will bring together Al-Akhshabayn (i.e. the two mountains that stand opposite to each other at the extremities of Makkah) to crush them in between.' The Prophet, sallallaahu ‘alayhi wa sallam, said to him: “I rather hope that Allaah will bring forth from their loins (i.e. their descendants) people who will worship Allaah alone, and will not associating anything to Him (in worship).” [Al-Bukhari and Muslim]

Fourthly, whoever insults the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, is to be executed for that takes one out of the fold of Islam. This ruling applies to Muslim individuals; however, executing non-Muslims who are Thimmi (non-Muslims living in an Islamic state) is not a unanimous agreement among the scholars. Even if we suppose that it is obligatory to execute whoever does this, it may be left for the interest of softening the non-Muslims' hearts towards Islam as stated by Ash-Shawkaani in Nayl Al-Awtaar.

Fifthly, as regards the poets whom the Prophet, sallallaahu ‘alayhi wa sallam, ordered to be executed on the Conquest of Makkah  such as Ka’b ibn Zuhayr and ‘Abdullaah ibn Khatal, then this is not something related to the Prophet, sallallaahu ‘alayhi wa sallam, in his own self. That is because he, sallallaahu ‘alayhi wa sallam, never took revenge for himself; rather, it is related to challenging the message of Islam and averting people from the Way of Allaah The Almighty, and making the Prophet, sallallaahu ‘alayhi wa sallam, and his companions a subject of satire because of their religion. Some of them embraced Islam and then apostated such as Ibn Khatal. Some others embraced Islam afterwards and the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, pardoned them such as Ka‘b ibn Zuhayr . For more benefit, please refer to Fatwa 188523.

Allaah Knows best.