What is the difference between "And there is no deity except Allah" and "There is no deity except Allah," and does "There is no deity except Allah" negate the whispers of the existence of other deities, along with a request for an explanation of Islamic creed?

Both phrases, "There is no god but Allah" (لا إله إلا الله) and "There is no god except Allah" (وما من إله إلا الله), affirm divinity for Allah and negate it from all others. The meaning of "There is no god except Allah" (وما من إله إلا الله) is "And there is no god except Allah" (وما إله إلا الله), and it denotes comprehensiveness due to the addition of "min" (مِنْ).

To repel intrusive thoughts (waswas), one says, "I believe in Allah" (آمنت بالله) or "I believe in Allah and His messengers" (آمنت بالله ورسله). The remembrance of Allah expels intrusive thoughts and Satan.