How can I prove Islam to someone who is a deist, who only believes in a creator that does not communicate with humans, and believes that great personalities such as Musa, Isa, and Muhammad (peace be upon them all) were just good people who were trying to reform people for the better? How can I prove it to someone who believes in no books or Prophets?
You can present your thoughts in some of the following methods:
1. To prove to him the necessity of having a messenger from God, in the following way:
The Creator must be All-Perfect because He is Absolute and free of limitations. One aspect of His Perfection is that He is All-Merciful and Wise. His Mercy would lead Him to make himself known to his creatures because for them to know Him would be the greatest pleasure they could attain.
His Wisdom would also cause Him to make Himself known because this would give purpose to His creation becuase without knowledge of Him their existence would be all-material and therefore ultimately purposeless and in vain. So, its necessary for Him to introduce Himself and His expectations from us in two ways:
a. an inner voice which is a common sense from within us to achknoweldge that there is a Creator and that this world could not have come out of the blue, and that there must be an aim and a purpose from this creation. This inner voice makes man a deist but man’s search for truth demands for more details knowledge.
b. Thus the Merciful God appointed certain humans, i.e. prophets, who are infallible from any sin or major mistakes, who were the most truthful and trustworthy people of their time, to reveal to them as much as truth as they could take and to share them with their fellow humans.
2. There have been many divine prophets throughout history. They all claimed to be the Messengers of God. The essence of the messages they shared with mankind is the same. They all acknowledged each other. They have coupled their claims with miracles; e.g. reviving a dead back to live, splitting the Nile into two, enabling people to hear the glorification of God from pebbles, etc. all by the Leave of God. They did not call to themselves, instead they always called to the worship of one unique God. Their message is compatible with our inner voice. We have not received any message from God (whom we know and believe in His existence) that denounces them. Therefore, if we believe in God we must also believe in His message and messengers.
Answered by: Sheikh Mansour Leghaei