I don't require proofs as I already know there's a God.
Actually, you don't "know" there is a god, loverofhumanity.
What you actually have, is "faith" and "belief" that there is a god. Meaning you "believe" there is a god.
There is a distinction between "believing" and "knowing".
With religion, it is all about "believing", and doesn't matter if what you believe in, is real or not, so you just accept it as if it was "real", hence this acceptance what people called "conviction" or "faith".
Knowing is different in the sense that it requires confirmation or verification.
The "knowledge" you think you have - all about your god (Allah), about the miracles (including resurrection and afterlife) and prophecies, about the text (Qur'an), and even about your prophet, are not really knowledge, because you have no way to "verify" they are all real or true.
What you really have, are again based on "belief" and "faith".
For instance, you believe - as all other Muslims do - that Muhammad met the archangel Gabriel, in 610 CE, which Muhammad claimed that angel came on behalf of Allah, and taught him the Qur'an.
But how do you or any Muslim know that Muhammad was speaking the truth?
No else had witnessed such a meeting between him and the angel. All you have is the hearsay of one man.
That's not "knowing", that's "believing", because there are no possible ways to verify what Muhammad say is true, and no way to verify the existence of archangel. How do you verify that the Qur'an come from the angel?
Like with the angel, the Qur'an is based on hearsay.
You believe that the scripture was transmitted from words of mouth, from Gabriel to Muhammad, because you believe that Muhammad was illiterate.
His illiteracy may be true, but Muhammad's direct source (Gabriel) is most likely not.
Muhammad was about 40 years old when he claimed to have met Gabriel. There have been Christian preachers coming and going in the Arabian peninsula for centuries, and there have been tribes of Jews living in the western coast of Arabia for some generations before Muhammad was born.
Not every converts to Christianity could read the gospels. Being capable to read is not a requirement to joining a religion. All it required is that Arabs listen with their ears to Christian preaching out in public.
You are forgetting that Jesus that didn't write anything down for anyone to read. All his teaching come from orally presenting to audience, whether within privacy of homes of his hosts, or for a much larger audience by speaking out in public, such as on the streets, or in the marketplace, or at the countryside.
Even his disciples or apostles learn from Jesus without reading materials. They would listen and memorise what being taught. And his disciples can pass on what they have learned to new audience.
Not everyone can read and write.
And Jews don't always rely on writing alone. Many of their stories were passed down through generations, hence oral tradition.
For example, there is the Written Torah, thus Genesis, Exodus, Leviticus and Numbers were recorded in scrolls and parchment, but there were also Oral Torah, which were passed down for generations, before they were written down by rabbis, starting from the fall of Jerusalem in 70 CE, in works, such as the Talmud, Midrash and Aggadah.
Some of the stories in the Aggadah, have found its way in the Qur'an. For instance, in Qur'an 27, you have King Solomon have the abilities to control winds and jinns, understand the languages of birds and ants. These abilities don't appear in the 1 Kings (bible), but they do appear in Jewish folklore in oral tradition and in the written Aggadah. The story about Solomon's gifts were greatly exaggerated. Jewish storytellers can easily tell these stories, without the need for people to read them.
Although I cannot show you any evidence that Muhammad learned all these stories from Jews and Christians, but they were present in Arabia, it is far more logical that the younger Muhammad heard all these stories from Jewish storytellers or Christian preachers than that an angel visited Muhammad.
According Muhammad's biography, Muhammad's uncle took him in, as a trader he took the orphan, to Syria. Do you Muhammad go to Syria, without hearing a single Christian preaching out in public?
And during that trip, one Syrian monk was said to have prophesied that Muhammad would become a prophet. But of course, there are no way to verify any of, because there are no reliable sources to Muhammad's life, and Islamic biographers and historians have the tendencies to exaggerate and distort any event in Muhammad's life, making it hard to verify anything.