Among what the Islamic shari’ah asserts is the binding and coupling of the testimony of oneness for Allah and the testimony of the calling and message of prophet Muhammad (peace and blessings of Allah be upon him). Examples of such linking are in the adhan for salaat and in the iqaamah for it. Additionally, in a hadith the prophet (peace be upon him) teaches:
“Islam was built upon five pillars: to witness that there is no deity except Allah, and that Muhammad is the messenger of Allah… .”It represents what a mukallaf (one who is legally capable, liable for one’s actions, and obliged to perform required acts, which in Islamic law, shari’ah, starts at puberty) is required to believe. It must be understood together, and are pronounced together as a testimony of belief. As for writing it interwoven, nothing is available neither in the Book of Allah nor in the Sunnah of the Prophet (peace and blessings of Allah be upon him). As a result, there is great danger in this. For it has a resemblance to the false precept in the Christian faith of trinity, and the concept that the father and the son and the holy spirit are one deity. Further, it could be construed as an emblem representing the false faith of the unity of existence. In addition, it may be used as support for the extremism in the Prophet and worshipping him with Allah.
Therefore, writing the name of Allah (the Most High) with the name of his prophet Mohammed (peace and blessings of Allah be upon him) in this way, i.e. making the letters of their names interwoven and the crossing of the letters of each of their names with the other, must be prevented. It is even not permissible to write (Allah - Muhammad) on the door of the masjid, nor in other locations, due to the confusion, misrepresentation, and serious concerns described and warned of above.
Sheikh Muhammed Salih Al-Munajjid