A while back I posted the following puzzle: Who has said that there is no God but Allah and that Prophet Muhammad is His Messenger but is not nor has ever been a Muslim?
The answer is Allah. In the Quran, Allah says, “GOD – there is no deity save Him, the Ever-Living, the Self-Subsistent Fount of All Being.” (2:255, Ayatul Kursi, The Sign of the Throne) So that takes care of the first part, saying that there is no God but Allah.
Then in Surah Ya-Seen, Allah says, “Verily, thou art indeed one of God�s message-bearers, ” speaking to Prophet Muhammad, peace be upon him (36:3).
But what about the claim that Allah is not Muslim? Of course Allah attests to the truth of Islam, however one cannot call HIm Muslim. If He were Muslim, He would have to pray. But to whom would He pray? To Himself? Also, what sense would there be in fasting for a being that needs no food?
Therefore, Allah is the only one to say the Kalima without being a Muslim.