Did Prophet Muhammad assassinate his critics?

It is said Prophet Muhammad assassinated a man only for criticizing him. Is Islam intolerant of criticism?

The story cited in this regard is the killing of Ka’b ibn al-Ashraf, who was a leader among the armies that were fighting a war of extermination against the Muslims, as is made clear in the several narrations concerning this incident. He was killed because he was an enemy combatant who also criticized Islam in poetry. Anti-Muslim writers only cite his poetry while they ignore his unwarranted aggression.

في هذا كله أنه لم يقتلهم بمجرد سبهم وإنما كانوا عونا عليه ويجمعون من يحاربونه ويؤيده

In these traditions it is shown that they were not killed merely for their insults. Indeed, they were only killed due to their aiding the enemy and preparing for war against him.

Ka’b ibn Al-Ashraf had made known his support for violence against the Muslim community, so killing him was done as a legitimate act of self-defense, not simply because he had criticized the Prophet (ṣ). Rather, the Prophet (ṣ) condemned any assassination that violates a peace treaty, pledge, promise, or security agreement.

Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said:

الْإِيمَانُ قَيَّدَ الْفَتْكَ لَا يَفْتِكُ مُؤْمِنٌ

Faith has prevented treacherous assassination. A believer does not assassinate.

مَعْنَى الْحَدِيثِ أَنَّ الْإِيمَانَ يَمْنَعُ مِنَ الْفَتْكِ الَّذِي هُوَ الْقَتْلُ بَعْدَ الْأَمَانِ غَدْرًا

The meaning of the tradition is that faith prohibits assassination, which is to treacherously kill a person after pledging them security.

Source: ‘Awn al-Maʻbūd 2769

In fact, the Prophet (ṣ) never took revenge for acts of abuse against himself, but instead he would only implement justice with due process.

Aisha reported:

وَمَا انْتَقَمَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لِنَفْسِهِ إِلَّا أَنْ تُنْتَهَكَ حُرْمَةُ اللَّهِ فَيَنْتَقِمَ لِلَّهِ بِهَا

The Messenger of Allah, peace and blessings be upon him, did not take revenge for anything against himself, but if the sacred limits of Allah were violated, he would retaliate for the sake of Allah.

There were many instances in the Prophet’s life in which he was insulted, mocked, and harmed by his enemies, and he responded with patience, forbearance, and forgiveness.

Aisha reported: A group of Jews asked permission to visit the Prophet and when they were admitted they said, “Death be upon you.” I said to them, “Rather death and the curse of Allah be upon you!” The Prophet, peace and blessings be upon him, said:

يَا عَائِشَةُ إِنَّ اللَّهَ رَفِيقٌ يُحِبُّ الرِّفْقَ فِي الْأَمْرِ كُلِّهِ

O Aisha, Allah is kind and He loves kindness in all matters.

This was because the Prophet would apply the teachings of the Quran which council forbearance and forgiveness in the face of insults and mockery.

Allah said:

خُذِ الْعَفْوَ وَأْمُرْ بِالْعُرْفِ وَأَعْرِضْ عَنِ الْجَاهِلِينَ

Show forgiveness, enjoin what is good, and turn away from the ignorant.

Surat al-A’raf 7:199

And Allah said:

وَعِبَادُ الرَّحْمَٰنِ الَّذِينَ يَمْشُونَ عَلَى الْأَرْضِ هَوْنًا وَإِذَا خَاطَبَهُمُ الْجَاهِلُونَ قَالُوا سَلَامًا

The servants of the Most Merciful are those who walk upon the earth in humility and when the ignorant address them harshly, they say words of peace.

Surat al-Furqan 25:63

And Allah said:

وَإِذَا سَمِعُوا اللَّغْوَ أَعْرَضُوا عَنْهُ وَقَالُوا لَنَا أَعْمَالُنَا وَلَكُمْ أَعْمَالُكُمْ سَلَامٌ عَلَيْكُمْ لَا نَبْتَغِي الْجَاهِلِينَ

When they hear ill speech, they turn away from it and say: For us are our deeds, and for you are your deeds. Peace be upon you, for we seek not the way of ignorance.

Surat al-Qasas 28:55

And Allah said:

فَاصْبِرْ عَلَىٰ مَا يَقُولُونَ وَسَبِّحْ بِحَمْدِ رَبِّكَ قَبْلَ طُلُوعِ الشَّمْسِ وَقَبْلَ الْغُرُوبِ

Be patient over what they say and exalt the praise of your Lord before the rising of the sun and before its setting.

Surat Qaf 50:39

And Allah said:

وَاصْبِرْ عَلَىٰ مَا يَقُولُونَ وَاهْجُرْهُمْ هَجْرًا جَمِيلًا

Be patient over what they say and avoid them with gracious avoidance.

Surat al-Muzammil 73:10

In sum, the Prophet (ṣ) did not kill anyone merely because he was insulted, but rather he performed military operations against aggressors in defense of the Muslim community and their freedom to practice Islam.