For that reason, Bediuzzaman stated that Hazrat Mahdi's (as) first duty is to combat Darwinist, materialist and atheist philosophies based on denial of Allah and to entirely lift the influence that these philosophies have over people:

And he [(Hazrat Mahdi (as)] will have three great duties; the first IS TO SAVE THE FAITH, IN SUCH A WAY AS TO COMPLETELY SILENCE MATERIALIST PHILOSOPHY that spreads among people under the influence of science and philosophy through the scourge of Darwinism, materialism and atheism. To protect believers from heresy... (Emirdağ Addendum, p. 259)

Hazrat Mahdi's (as) primarily proving the invalidity of Darwinism and setting out the fact of Creation is an important means of communicating the word also used by prophets in the past. Hazrat Musa (as) also first proved that belief in evolution is wrong and revealed Allah's creation with supporting evidence. The myth of evolution is a superstitious religion going back as far as Sumerian times. Belief in evolution was also widespread in Ancient Egypt. Pharaoh and his supporters believed in a primitive version of contemporary Darwinism and espoused that heretical belief. This is perfectly apparent from an examination of the history of religion in Egypt.  

According to ancient Egyptian superstition, "Snakes, frogs, worms and rats form in mud produced by the River Nile flooding its banks."¹ In other words, one of the basic false claims of Darwinism "living things came into being by chance, out of mud," was also widespread in Ancient Egypt.  Therefore, when the Hazrat Musa (as) began preaching he first set about freeing the Egyptians from that error and eradicated evolutionist thinking. When Hazrat Musa (as) went to preach to Pharaoh, Pharaoh asked him, "What about the previous generations" (Surah Ta Ha, 51) in a manner reminiscent of the questions and mindsets of contemporary Darwinists. Inspired by Allah, Hazrat Musa (as) replied "Knowledge of them is with my Lord in a Book. My Lord does not misplace nor does He forget." (Surah Ta Ha, 52) and described the fact of Creation to Pharaoh with full supporting evidence. 

The Qur'an reveals that when Hazrat Musa (as) cast his staff onto the ground it turned, by Allah's will, into a living snake. When he threw his staff onto the ground, a dead piece of wood turned into a living snake, and when he picked it up again, a living snake turned back into a dead piece of wood. When he threw it down again, it again came to life as a snake. In other words, inanimate matter comes to life, dies, then comes back to life again. Through this miracle, Allah reveals His constant creation. In verses we are told:

He threw it down AND SUDDENLY IT WAS A SLITHERING SNAKE. He said, 'Take hold of it and have no fear. We will return it to its original form. (Surah Ta Ha, 20-21) "Throw down what is in your right hand. IT WILL SWALLOW UP THEIR HANDIWORK. Their handiwork is just a magician's trick. Magicians do not prosper wherever they go." (Surah Ta Ha, 69) Throw down your staff.' Then when he saw it SLITHERING LIKE A SNAKE he turned and fled and did not turn back again. 'Have no fear, Musa. In My Presence the Messengers have no fear - (Surat an-Naml, 10)

When Hazrat Musa (as) threw his staff onto the ground, an inanimate piece of wood turned, as a blessing from Allah, into a fast-moving snake that immediately swallowed all the false snakes produced by the members of Pharaoh's entourage. People thus saw that this snake was a real snake. Because the act of swallowing was a sign that the snake was alive, that it had a stomach, that it ate, and was therefore a living thing. They then saw the snake try to escape, that it could move, another indication that it was alive. The people there thus came to grasp creation and even Pharaoh's assistants saw Allah's sublime creation and immediately prostrated themselves on the ground and believed in Him.

Through this means of communicating the word employed by the Hazrat Musa (as), Allah showed one example of how He creates life from nothing. Inanimate matter came into being by Allah's will alone, just by His commanding it to 'Be!' By the end of this encounter, during which Allah blessed him with a miracle, Hazrat Musa (as) had demolished the ancient Egyptians' superstitious evolutionary beliefs at a single stroke. Even those people who opposed Hazrat Musa (as) immediately grasped through truth through this mode of communication and abandoned their superstitious beliefs. 

A similar means of communication to that of the Hazrat Musa (as) was used by the Hazrat 'Isa (as). In his preaching, he also strove against pagan thinking and beliefs and a Judaism that had become corrupted. He told people the truth, but he, too, first demonstrated the fact of Creation. It is revealed in the Qur'an how Hazrat 'Isa (as) made something in the shape of a bird out of a piece of clay and then breathed on it, at which, by Allah's will, it turned into a living creature: 

Remember when Allah said, "Isa, son of Maryam, remember My blessing to you and to your mother when I reinforced you with the Purest Spirit so that you could speak to people in the cradle and when you were fully grown; and when I taught you the Book and Wisdom, and the Torah and the Gospel; and WHEN YOU CREATED A BIRD-SHAPE OUT OF CLAY BY MY PERMISSION AND THEN BREATHED INTO IT AND IT BECAME A BIRD BY MY PERMISSION... (Surat al-Ma'ida, 110)

This bird comes to life through no natural cause, but through the will of Allah and a miracle. A living bird emerging from inanimate matter is one of the examples of Almighty Allah's sublime creation independent of prior models or natural causes.  Hazrat 'Isa (as) also first demonstrated the fact of Creation and enabled them to understand how Allah brings everything into being from nothing. By this miracle bestowed on him by Allah, Hazrat 'Isa (as) revealed the illogicality and invalidity of evolutionist thinking.

These methods employed by Hazrat Musa (as) and Hazrat 'Isa (as) clearly reveal the importance of "starting to preach by proving Creation.' When Hazrat Mahdi (as) begins his work Allah will also guide him to use the same technique. When he appears he will first demonstrate the invalidity of Darwinism, prove Creation and, as revealed by Bediuzzaman Said Nursi, will wage an intellectual struggle of such a kind AS TO TOTALLY SILENCE Darwinism and materialism.  "Completely neutralizing Darwinism and materialism all over the world" will be Hazrat Mahdi's (as) first task. And with the collapse of materialism, atheism and Darwinism, Hazrat Mahdi (as) will be instrumental in bringing all mankind to faith.