What is the ruling on insulting the Prophet (saw)?

In a Nutshell: The classical jurists agree it is forbidden to insult the Prophet (saw) with most agreeing the punishment to be capital punishment, others arguing non-Muslim insulters should receive a discretionary punishment. Muslims who mock should be asked to repent before the application of any capital punishment. Evidences "Those who harm Allah and His Messenger, Allah has cursed them in this world and in the Next, and has prepared for them a humiliating punishment." (Qur'an 33:57) "If you ask them, they will say, 'We were only plunging and playing.' Say, 'What, were you then mocking Allah, His signs and His Messenger? Make no excuses. You have disbelieved after your belief."' (Qur'an 9:67-68) "Whoever curses a Prophet, kill him. Whoever curses my Companions, beat him." (Tabarani, Daraqutni) Allah's Messenger (saw) said, "Who is willing to kill Ka'b bin Al-Ashraf who has hurt Allah and His Apostle?" Thereupon Muhammad bin Maslama got up saying, "O Allah's Messenger (saw)! Would you like that I kill him?" The Prophet (saw) said, "Yes," Muhammad bin Maslama said, "Then allow me to say a (false) thing (i.e., to deceive Ka'b). "The Prophet (saw) said, "You may say it." Then Muhammad bin Maslama went to Ka'b and said, "That man demands sadaqa (i.e., zakat) from us, has troubled us, and I have come to borrow something from you." Ka'b said, "By Allah, you will get tired of him!" ... So they killed him and went to the Prophet (saw) and informed him." (Sahih al-Bukhari 4037, Muslim 1801) The Prophet commanded that a group of unbelievers who used to injure and curse him, like an-Nadr ibn al-Harith and Uqba ibn Abi Mu'ayt, be killed. He promised that a group of them would be killed before and after the conquest. They were all killed except for those who hurried to become Muslim before they were overpowered. Al-Bazzar related from Ibn 'Abbas that Uqba ibn Abi Mu'ayt cried out, "O company of Quraysh, why is it that I alone among you am to be killed without war?" The Prophet said, "For your disbelief and your forging lies against the Messenger of Allah." A blind man had a freed concubine (Umm walad) who used to insult the Prophet (saw) and say bad things about him. He told her not to do that but she did not stop, and he rebuked her but she did not heed him. One night, when she started to say bad things about the Prophet (saw) and insult him, he took a short sword or dagger, put it on her belly and pressed it and killed her. A child fell between her legs, and became covered by blood. The following morning that was mentioned to the Messenger of Allah (saw). He called the people together and said, “I ask by Allah the man who has done this action and I order him by my right over him that he should stand up.” The blind man stood up and said, “O Messenger of Allah, I am the one who did it; she used to insult you and say bad things about you. I forbade her, but she did not stop, and I rebuked her, but she did not give up her habit. I have two sons like pearls from her, and she was kind to me. Last night she began to insult you and say bad things about you. So I took a dagger, put it on her belly and pressed it till I killed her.” Thereupon the Prophet (saw) said: “Bear witness, there is no blood money due for her. (Abu Dawood 4361; Daraqutni 3/112; Tabarani; Hakim; Nisa'i, 4081) Abd al-Razzaq mentioned that a man cursed the Prophet, causing the Prophet to say, "Who will save me from my enemy?" Az-Zubayr said, "I will." He sent az-Zubayr and he killed him. It is related that a woman used to curse the Prophet and he said, "Who will save me from my enemy?" Khalid ibn al-Walid went out and killed her. Al-Mujahir ibn Abi Umayya, the Amir of Yemen, reported to Abu Bakr that a woman there in the time of the Ridda chanted curses against the Prophet, so he cut off her hand and pulled out her front teeth. When Abu Bakr heard that, he said to him, "If you had not done what you already did, I would have commanded you to kill her because the hadd regarding the Prophet is not like the hadd regarding others." Ibn Abbas said that a woman from Khatma satirised the Prophet and the Prophet said, "Who will deal with her for me?" A man from her people said, "I will, Messenger of Allah." The man got up and went and killed her. He told the Prophet who said, "Two goats will not lock horns over her." There is also the letter of Umar ibn Abd al-Aziz to his governor in Kufa. He had asked his advice about killing a man who had cursed Umar. Umar wrote back to him, "It is not lawful to kill a Muslim for cursing anyone except the Messenger of Allah. Whoever curses him, his blood is lawful." Harun ar-Rashid asked Malik about a man who had reviled the Prophet and he mentioned to him that the fuqaha of Iraq had given a fatwa that he be flogged. Malik became angry and said, "Amir al-Mu'minin! There is no continuation for a community after it curses its Prophet! Whoever curses the Companions of the Prophet is to be flogged." Scholar's Opinions The Shafi'i jurists Ibn Mundhir and Abu Sulayman al-Khattabi (d. 996) stated all men of learning agree that whoever insults the Prophet (saw) is to be killed citing Ka'b bin al-Ashraf, a seventh-century Jewish poet, as the first to be executed for insulting the Prophet. Subki himself concurs with this view stating minor differences in the Shafi'i school were nothing but pointless debates whilst in his Khulasa, al-Ghazali concludes insulting the Prophet “is specified for the dhimmis” and is the same as not paying the jizya, indeed, “the opinion is that for this [crime] their repentance is not accepted and they are killed on the spot.” (Taqi al-Din Subki, al-Sayf al-Maslul, p. 233) The Maliki Qadi Iyad’s Shifa was innovative in its detailed catalogue of insults, providing a plethora of examples of Muslims who insulted Muhammed, most of whom lived outside of al-Andalus though seldom mentioning non-Muslims. Another Maliki jurist, Ibn al-Qassem noted: "Whoever insults the messenger of Allah (saw), curses, defames or belittled him should be killed if he is a Muslim without being asked to repent." The thirteenth-century Hanbali jurist Ibn Taymiyyah wrote a long treatise about insulting the Prophet (saw) called al-Sarim al-Maslul ala Shatim al-Rasul where he argued that the one who insulted the Prophet (saw) had committed a hadd crime and could not avoid the death penalty through repentance or conversion. He used a variety of sources to build his case, the most important consisting of events from seerah literature where the Prophet (saw) dealt harshly with those who insulted him. He supplemented this with statements by early figures in the Ḥanbali, Maliki, and Shafi'i schools with Qadi Iyad's Shifa' an important reference. Abu Hanifa held non-Muslims who insult the Prophet (saw) "are not to be killed, because their unbelief is worse...” (Ibn Taymiyyah, al-Sarim al-Maslul ala Shatim al-Rasul, p.3). Other Hanafi jurists held a similar position including, al-Tahawi (d. 933), who specified a discretionary punishment for non-Muslims other than death and al-Quduri (d. 1037), al-Marghinani (d. 1197), and Ibn al-Humam (d. 1457) who did not specify punishments (al-Quduri, al-Mawsu'a al-fiqhiyya al-muqarana: al-Tajrid; Ibn al-Humam, Sharh Fath al-qadir). Badr al-Din al-Ayni's (d. 1451) commentary on the Hidaya of al-Marghinani notes that al-Atrazi (d. 1357) ruled that a non-Muslim insulter of the Prophet be killed (Badr al-Din al-Ayni, al-Binaya fi sharh al-Hidaya​​​​​​) becoming the norm among Hanafis through the Ottoman period. In his commentary on Hanafi fiqh, the Crimean jurist Ibn al-Bazzaz (d. 1424) deemed Ibn Taymiyyah’s treatise as the authoritative work on the subject arguing, "[the insulter] be killed as a ḥadd without any possibility for repentance.” The Ottoman jurist Mulla Khusrev (d. 1480) cited his work approvingly for the position that the Hanafi school demands both Muslim and non-Muslim insulters of the Prophet to be killed and repentance for the crime is impossible. Conclusion In conclusion the classical jurists agree it is forbidden to insult the Prophet (saw) with most agreeing the punishment to be capital punishment, others arguing non-Muslim insulters should receive a discretionary punishment. Muslims who mock should be asked to repent,