What is the ruling on Christians insulting Islam and Muslims, and how should their mockery and insults be dealt with?

The hatred of some disbelieving factions towards Islam is due to their nature and the sealing of their hearts, because they chose misguidance over guidance. This makes them see falsehood as truth and they will not be guided, even if they were to see every sign. This is from the wisdom of Allah Almighty, who guides whom He wills and leads astray whom He wills. It is obligatory to invite disbelievers [to Islam] with wisdom and good admonition for those who are qualified to do so. As for the general public, they should not review the words of disbelievers or argue with them. Rather, they should focus on learning their religion and keeping away from sources of doubt.