What is the Sharia ruling on how to deal with those who insult the Messenger of Allah, peace and blessings be upon him, and his wives, and is a Muslim sinful if he does not respond to them?

The stance toward those who insult the Prophet (peace be upon him) and his wives is determined by their nature. If they are open to dialogue, then inviting them [to Islam] is an obligation upon whoever is able, for Allah the Almighty says: "Say, 'This is my way; I invite to Allah with insight, I and those who follow me. And exalted is Allah; and I am not of those who associate others with Him.'"

However, if they do not accept, or if destroying their platform becomes necessary to deter their evil, then this becomes obligatory upon whoever is able. This is because defending the Prophet (peace be upon him) and his honor is among the most incumbent obligations, for Allah the Almighty says: "That you may believe in Allah and His Messenger and honor him and respect him and exalt Him morning and evening." This destruction, however, must not lead to a greater evil.