One of the Arkaan of faith is to believe in the revelation of the revealed books which includes the Qur’an. If one rejects a Surah, a verse, an Ayah or a letter from the Qur’an then one falls into disbelief. Can you please give me references from the Qur’an and the Hadith to support this claim?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Believing in the revealed Books is one of the pillars of Iman (faith).  If someone denies one verse or letter from them it is like he is denying the whole book.  If someone denies the Qur'an, he becomes a Kafir according to the consensus of the Ulamah (scholars).

There are many verses from the Qur'an about the evidence of this consensus.

Allah Says (interpretation of meaning) about the people of the Book who disbelieve in the Qur'an: {And when there came to them (the Jews), a Book (this Qur'ân) from Allâh confirming what is with them [the Taurât (Torah) and the Injeel (Gospel)], although aforetime they had invoked Allâh (for coming of Muhammad ) in order to gain victory over those who disbelieved, then when there came to them that which they had recognized, they disbelieved in it. So let the Curse of Allâh be on the disbelievers. How bad is that for which they have sold their own selves, that they should disbelieve in that which Allâh has revealed (the Qur'ân), grudging that Allâh should reveal of His Grace unto whom He will of His slaves. So they have drawn on themselves wrath upon wrath. And for the disbelievers, there is disgracing torment.}[2:89-90].

Allah also Says (interpretation of meaning) in their regard: {Then do you believe in a part of the Scripture and reject the rest? Then what is the recompense of those who do so among you, except disgrace in the life of this world, and on the Day of Resurrection they shall be consigned to the most grievous torment. And Allâh is not unaware of what you do. }[2:85].  

Allah knows best.