How the Qur’aan states true believers ?

“Those who follow the messenger, the prophet who can neither read nor write, whom they
will find described in the Torah and the Gospel (which are with them). He will enjoin on
them that which is right and forbid them that which is wrong. He will make lawful for
them all good things and prohibit for them only the foul; and he will relieve them of their
burden and the fetters that they used to wear. Then those who believe in him, and honour
him, and follow the light which is sent down with him: they are the successful”.
(The Qur’aan 7:157)

Any one had made any corruption in quran verses?any one can make any corroption in quran verses?

(15:9)
"We have, without doubt, sent down the Message; and We will assuredly guard it 
(from corruption)."

which is the most currect guide to mankind?

(2:185)
"Ramadan is the (month) in which was sent down the Qur’an, as a guide to mankind, also clear
(Signs) for guidance and judgement (between right and wrong)."

For what we are repent to allah earliar,we can repent when death approaches ?

(4:17)
'But of no avail is repentance of those who do evil until death approaches
any one of them and then he says: 'Now I repent.' Nor is the repentance 
of those who die in the state of unbelief of any avail to them. For them 
We have kept in readiness a painful chastisement.'

Is Allah is the very Truth?

(31:30)
'This is because Allah is the very Truth, and all 
those whom the people invoke instead of Allah, are 
false, and (this is because) Allah alone is the 
High, the Great.'  

who causes the night to pass into the day and the day into the night?

(31:29)
'Do you not see that Allah causes the night to pass into the day and 
the day into the night? He has subjected the sun and the moon, each 
voyaging (in its course) till an appointed time. And (do you not know) 
that Allah is aware of whatever you do?' 

Is'nt Allah knows every thing that happening in the world ?

(6:59)
'He has the keys to the realm that lies beyond the reach of
human perception; none knows them but He. And He knows what 
is on the land and in the sea; there is not a leaf, which 
falls that He does not know about and there is not a grain 
in the darkness of the earth or anything green or dry, 
which has not been recorded in a Clear Book.  He recalls 
your souls by night, and knows what you do by day; and then
He raises you back each day in order that the term appointed
by Him is fulfilled. Then to Him you will return whereupon 
He will let you know what you have been doing. And He alone 
holds sway over His servants and sets guardians over you till
death approaches any of you and Our deputed angels take his 
soul, neglecting no part of their task. Then all are restored
to Allah, their true protector. Behold, His is the judgment
.He is the swiftest of those who take account.'