What is the ruling of the Shari'ah on bringing mobile phones into mosques, especially given the frequent ringing during prayer and the disturbance this causes to worshippers?

Among Allah's blessings is the facilitation of communication means. Gratitude for them lies in using them for good, keeping them away from evil, and not allowing them to become a cause for hindering obedience to Allah. It is disliked for a worshipper to carry anything that distracts him from khushu' (devotional humility). The angels are harmed by what harms human beings. Furthermore, the Prophet, peace be upon him, encouraged lowering one's voice when reciting the Qur'an so as not to disturb others. Therefore, mobile phones must be switched off upon entering mosques to avoid disturbing the worshippers.