The core of Islam's belief system is generally contained in the primary proclamation "There is no god save Allah, and Muhammad is His messenger." This simple statement is recited by all Muslims during their ritual prayers tens of times in the day and it serves as an affirmation of the divine unity of God; He is indivisible, without partner, and is the Creator and Sustainer of the heavens and the earth. Inherent in that belief is belief in the unseen entities as related by God via His prophets. These include His angels, who are beings created from light that hymn the praises of God tirelessly and carry out specific tasks as prescribed by Him, which include receiving souls upon death, recording the deeds of each individual, and acting as messengers to the human prophets. Satan is not a "fallen angel", but rather a different being created from fire and he disobeyed God when he was asked to prostrate before Adam as a sign of respect, the first man and prophet.
Muslims also believe in the universal message of the previous prophets, who include Jesus, Moses, Abraham, David, Solomon, Noah and others. While their specific law and ritual worship were limited to the communities they were sent to, they all embodied the universal message of belief in one God. The Prophet Muhammad, being the final prophet and messenger, also brought forth a universal system of law and ritual worship that superseded all that came before him.
Muslims also revere and respect the scriptures that were revealed before the Quran such as the Bible, Torah and Psalms of David. While Muslims maintain that current copies of these books have been marked by human intervention, unlike the Quran which God Himself has vowed to preserve, they nonetheless uphold the sacrosanctity of these scriptures in their original form.
Belief in the ultimate destiny of man being subject to God's will is also a core belief. While Muslims would object to being called fatalistic, they hold that God's knowledge of all affairs, however minute and his omnipotence know no bounds. Regardless, man is enjoined to work for the good of society and worship God, even though the final outcome is known to Him.