What is your opinion on a message that says: "Which is more widespread: the Quran or mobile phones? Re-examine yourself!"?

If reminding people about the Qur’an and such matters aims to encourage them to pay attention to it, then there is no harm in that. It is hoped that this will be considered cooperation in goodness, guiding to it, enjoining what is right, forbidding what is wrong, and warning against abandoning the Qur’an. This is in accordance with the Almighty’s saying: ﴿And the Messenger has said, "O my Lord, indeed my people have taken this Qur'an as [something] abandoned."﴾, and His saying: ﴿And cooperate in righteousness and piety.﴾, and His saying: ﴿The believing men and believing women are allies of one another. They enjoin what is right and forbid what is wrong.﴾. Ibn al-Qayyim considered engaging in forbidden listening instead of listening to the Qur’an as one of Satan’s stratagems that turn hearts away from the Qur’an and make them devoted to immorality.