Allah invites you to Islam and tells you that it is He who sent down the Koran 57:7-9
57:7 Believe in Allah and His Messenger and spend (in charity) of that which He has made you successors. Whosoever of you believes and spends shall have a mighty wage.
57:8 Why is it that you do not believe in Allah, when the Messenger calls on you to believe in your Lord, and He has made a covenant with you if you are believers?
57:9 It is He who sends down clear verses to His worshiper, so that He brings you out of the darkness into the light. Indeed, Allah is the Gentle, the Most Merciful to you.