Reference: Fataawa Manaar al-Islaam – Question 8, Page 25
Question: What is the ruling regarding someone who abuses the religion or any of the prophets?
Response: Anyone who abuses the religion or abuses Allaah or His messenger, then he is a disbeliever – out of the fold of Islaam, and we seek refuge in Allaah [from that]. [This is the case] even if he believes he is a Muslim. Even the people of knowledge have said: Indeed whoever abuses Allaah, then he is a disbeliever, even if he was joking. And the evidence they use is His (Subhaanahu wa Ta’aala) saying:
{If you ask them, they declare: “We were only talking idly and joking.” Say: “Was it at Allaah, and His Aayaat and His Messenger that you were mocking?” Make no excuse; you have disbelieved after you had believed}, [Soorah at-Towbah, Aayahs 65-66].
So, everyone who abuses Allaah or His messenger, or His Book, or His religion, or any of the prophets ﷺ then he is a disbeliever. And it is upon these people to repent to Allaah (Subhaanahu wa Ta’aala) and return to Him (to Islaam), otherwise they will be given the glad tidings of the Fire of Hell.
We ask Allaah to guide them, and Allaah is the Expounder of success.