﴿ فَلَا تُطِعِ ٱلْكَٰفِرِينَ وَجَٰهِدْهُم بِهِۦ جِهَادًۭا كَبِيرًۭا ﴾

“hence, do not defer to [the likes and dislikes of] those who deny the truth, but strive hard against them, by means of this [divine writ], with utmost striving.”

Jihad with Qur'an (its propagation) is great Jihad وَجَاهِدْهُم بِهِ جِهَادًا كَبِيرً‌ا (And strive against them with it (the Qur'an) a great striving - 25:52). This is a Makkan verse when the injunction for Jihad, in the sense of fighting the infidels, had not been revealed. What is ordained in this verse is that you spread the message of Qur'an among the people at large. Propagation of Qur'anic message among people and to make them understand it is great Jihad whether it is by mouth, pen or any other means,