Islam is a set of beliefs which can be realized in the six pillars of faith, namely belief in Allah, His angels, His Books, His Messengers, the Last Day and the Divine Decree, the good of it and the bad of it. Allah the Almighty says, "The Messenger believes in what has been revealed to him from his Lord, and so do the believers: all of them believe in Allah, His Angels, His Books and His Messengers, [saying,] 'We make no distinction between any of His Messengers;' and they say, 'We hear and we obey. We implore Your forgiveness, O our Lord, and to You is the returning.'" (2:285) He also says, "Verily, We have created everything with qadar (Divine Preordainments of all things before their creation, as written in the Book of Decrees.)' (54:49)
Belief in Allah means the belief that He is the only true God and that He is one and has no partners at all. He is the only Lord who manages the affairs of the universe, the only true God who alone is worthy of worship, without any partners, who has the most beautiful names and the loftiest perfect attributes which are not likened to any of those of His creatures even though some of the attributes may be shared between the Creator and the created, for there is nothing like Him.
Taken from THIS IS ISLAM