First of all, we should stress that every Muslim should keep the words of tawheed from being humiliated. Part of the humiliation is to put such words on a mobile screen and enter the bathroom with the mobile. The bathroom is a place not suitable for the name of Allah to be taken into. Thus, one is not allowed to enter the bathroom while holding the mobile phone or even wearing a ring or anything else that contains Allah’s name.
Sheikh Ibrahim Salih Al-Husaini, Mufti of Nigeria, states the following: In fact, it is not allowed for a person to put the words that stand for the testifaction of faith ‘La ilaha illa Allah Muhammad Rasool Allah’) on the mobile screen, as the mobile may be taken to the bathroom. Things that contain the name of Allah should be kept far from impure places like WC.

However, if the person is quite sure that the words of tawheed (There is no god but Allah, Muhammad is the Messenger of Allah) will be kept remote from impurities (for example, if the person leaves his cell phone outside while entering the WC or switches it off before entering), then there is nothing wrong in having that words appear on his mobile.

It has become clear from the above fatwa that in entering the WC or any impure places, one should not take with him anything that bears the name of Allah. That’s why Muslim scholars made it impermissible for a person to enter the bathroom with rings carrying the name of Allah. Anas (may Allah be pleased with him) is reported to have said: “On entering the bathroom, the Prophet (peace and blessings be upon him) used to take off his ring.