Is a person who believes in the oneness of God and the prophethood of Muhammad (peace be upon him) considered a Muslim, even if they have not uttered the Two Testimonies (Shahadatayn) or performed the pillars of Islam, such as prayer, and what is the ruling on initiating greetings of peace with non-Muslims in such a case?

The aforementioned teacher is not a Muslim until he pronounces the two testimonies of faith (Shahadatayn) and disavows his false religion, because his mere praise of Islam does not make him a Muslim.

Based on this, this man is treated as a disbeliever (kafir). Therefore, it is not permissible to initiate greetings of peace (salam) with him, according to the majority of scholars, although some scholars have permitted it for a greater benefit or with a greeting other than the Islamic salutation.