Firstly:

There is no difference between using the Qur'aan or Sunnah as evidence, because both are Revelation (wahy) from Allaah to His Prophet Muhammad (Peace And Blessings Of Allaah Be Upon Him), and the Sunnah explains the Qur'aan. Allaah, may He be exalted, has commanded us to accept that which His Prophet (Peace And Blessings Of Allaah Be Upon Him) brought and to abstain from that which he forbade. Allaah says (interpretation of the meaning):

"And whatsoever the Messenger (Muhammad) gives you, take it; and whatsoever he forbids you, abstain (from it)"

[al-Hashr 59:7]

The Sunnah is the wisdom (al-hikmah) that is mentioned in the Book of Allaah in many verses, such as the following (interpretation of the meaning):

"Similarly (to complete My Blessings on you), We have sent among you a Messenger (Muhammad) of your own, reciting to you Our Verses (the Qur'aan) and purifying you, and teaching you the Book (the Qur'aan) and the Hikmah (i.e. Sunnah, Islamic laws and Fiqh — jurisprudence), and teaching you that which you used not to know"

[al-Baqarah 2:151]

"And treat not the Verses (Laws) of Allaah as a jest, but remember Allaah's Favours on you (i.e. Islam), and that which He has sent down to you of the Book (i.e. the Qur'aan) and Al-Hikmah (the Prophet's Sunnah — legal ways — Islamic jurisprudence) whereby He instructs you. And fear Allaah, and know that Allaah is All-Aware of everything"

[al-Baqarah 2:231]

What prompted us to point this out is what is said in the question about looking for Qur'aanic texts which prove the divine origin of Islam. If the question had been about texts of Revelation or evidence from the Qur'aan and Sunnah, that would have been better and more appropriate.

Secondly:

Islam is a divinely-revealed religion, and it is revelation (wahy) from Allaah, may He be exalted. The Qur'aan and Sunnah both come from Allaah. Allaah has made this religion the final religion, and has made its Prophet Muhammad (Peace And Blessings Of Allaah Be Upon Him) the final Prophet and Messenger.

Every attempt on the part of the kuffaar and atheists to destroy Islam or distort it has ended in failure and loss, because Allaah has guaranteed to protect the foundations of this religion, namely the Qur'aan and Sunnah.

This is sufficient evidence for the divine origin of Islam. Whoever studies the attempts to destroy Islam or distort the Qur'aan and Sunnah, and studies how Allaah has protected His religion, will know that if this religion was of human origin, the product of human thought, it would now be unknown, but Allaah promised to protect His religion, and moreover He gave us the glad tidings that it would prevail over all other religions and spread throughout the world.

There follow some of the Qur'aanic texts which show that Islam is divine in origin:

1 – Allaah says (interpretation of the meaning):

"This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islam as your religion"

[al-Maa'idah 5:3]

2 – Allaah says (interpretation of the meaning):

"Verily, We, it is We Who have sent down the Dhikr (i.e. the Qur'aan) and surely, We will guard it (from corruption)"

[al-Hijr 15:9]

3 – Allaah says (interpretation of the meaning):

"And (remember) when Allaah took the Covenant of the Prophets, saying: 'Take whatever I gave you from the Book and Hikmah (understanding of the Laws of Allaah), and afterwards there will come to you a Messenger (Muhammad) confirming what is with you; you must, then, believe in him and help him.' Allaah said: 'Do you agree (to it) and will you take up My Covenant (which I conclude with you)?' They said: 'We agree.' He said: 'Then bear witness; and I am with you among the witnesses (for this)'"

[Aal 'Imraan 3:81]

4 – Allaah says (interpretation of the meaning):

"Do they seek other than the religion of Allaah (the true Islamic Monotheism worshipping none but Allaah Alone), while to Him submitted all creatures in the heavens and the earth, willingly or unwillingly. And to Him shall they all be returned"

[Aal 'Imraan 3:82]

5 – Allaah says (interpretation of the meaning):

"Say (O Muhammad): 'I don't tell you that with me are the treasures of Allaah, nor (that) I know the Unseen; nor do I tell you that I am an angel. I but follow what is revealed to me.' Say: 'Are the blind and the one who sees equal? Will you not then take thought?'"

[al-An'aam 6:50]

6 – Allaah says (interpretation of the meaning):

"And when Our clear Verses are recited unto them, those who hope not for their Meeting with Us, say: 'Bring us a Qur'aan other than this, or change it.' Say (O Muhammad): 'It is not for me to change it on my own accord; I only follow that which is revealed unto me. Verily, I fear the torment of the Great Day (i.e. the Day of Resurrection) if I were to disobey my Lord.'

16. Say (O Muhammad): 'If Allaah had so willed, I should not have recited it to you nor would He have made it known to you. Verily, I have stayed amongst you a life time before this. Have you then no sense?'"

[Yoonus 10:15, 16]

7 – Allaah says (interpretation of the meaning):

"And We have also sent down unto you (O Muhammad) the Dhikr [reminder and the advice (i.e. the Qur'aan)], that you may explain clearly to men what is sent down to them, and that they may give thought"

[al-Nahl 16:44]

This indicates that the Sunnah is one of the sources of the divine sharee'ah.

8 – Allaah says (interpretation of the meaning):

"Indeed We have sent Our Messengers with clear proofs, and revealed with them the Scripture and the Balance (justice) that mankind may keep up justice. And We brought forth iron wherein is mighty power (in matters of war), as well as many benefits for mankind, that Allaah may test who it is that will help Him (His religion) and His Messengers in the unseen. Verily, Allaah is All-Strong, All-Mighty"

[al-Hadeed 57:25]

9 – Allaah says (interpretation of the meaning):

"O mankind! Verily, there has come to you a convincing proof (Prophet Muhammad) from your Lord; and We sent down to you a manifest light (this Qur'aan)"

[al-Nisa' 4:174]

10 – Allaah says (interpretation of the meaning):

"O mankind! There has come to you a good advice from your Lord (i.e. the Qur'aan, enjoining all that is good and forbidding all that is evil), and a healing for that which is in your breasts, — a guidance and a mercy (explaining lawful and unlawful things) for the believers"

[Yoonus 10:57]

11 – Allaah says (interpretation of the meaning):

"And thus We have sent to you (O Muhammad) Rooh (a revelation, and a mercy) of Our Command. You knew not what is the Book, nor what is Faith? But We have made it (this Qur'aan) a light wherewith We guide whosoever of Our slaves We will. And verily, you (O Muhammad) are indeed guiding (mankind) to the Straight Path (i.e. Allaah's religion of Islamic Monotheism).

53. The path of Allaah to Whom belongs all that is in the heavens and all that is in the earth. Verily, all matters at the end go to Allaah (for decision)"

[al-Shoora 42:52-53]

12 – Allaah says (interpretation of the meaning):

"By the star when it goes down (or vanishes).

2. Your companion (Muhammad) has neither gone astray nor has erred.

3. Nor does he speak of (his own) desire.

4. It is only a Revelation revealed"

[al-Najm 53:1-4]

13 – Allaah says (interpretation of the meaning):

"O Messenger (Muhammad)! Proclaim (the Message) which has been sent down to you from your Lord. And if you do not, then you have not conveyed His Message. Allaah will protect you from mankind. Verily, Allaah guides not the people who disbelieve"

[al-Maa'idah 5:67]

And there are many verses which speak of this principle. We advise you to ponder the Book of Allaah for yourself as you read it, and thus you will find what you are looking for and more, in sha Allaah. You can also seek the help of some trustworthy tafseers (commentaries) such as the Tafseer of Ibn Katheer or Ibn Sa'di, and so on.

In the Sunnah of the Prophet (Peace And Blessings Of Allaah Be Upon Him) there is evidence that points to the divine origin of Islam and proves that its source is Allaah, may He be glorified and exalted, and that the Prophet (Peace And Blessings Of Allaah Be Upon Him) is no more than the conveyor of the Message that his Lord revealed to him. For example:

1 – It was narrated that al-Miqdaam ibn Ma'di Karib al-Kindi said: The Messenger of Allaah (Peace And Blessings Of Allaah Be Upon Him) said: "I have been given the Book and something similar along with it." Narrated by Abu Dawood (4604) and classed as saheeh by al-Albaani in Saheeh Abi Dawood.

2 – It was narrated from Abu Hurayrah (may Allaah be pleased with him) that the Messenger of Allaah (Peace And Blessings Of Allaah Be Upon Him) said: "I do not give to you and I do not withhold from you, rather I am a distributor and I allocate things where I am commanded to." Narrated by al-Bukhaari (2949).

3 – It was narrated from Jubayr ibn Mut'im that a man came to the Prophet (Peace And Blessings Of Allaah Be Upon Him) and said: O Messenger of Allaah, which part of the land is worst? He said: "I do not know." When Jibreel (peace be upon him) came to him he said: "O Jibreel, which part of the land is worst?" He said: "I do not know, until I ask my Lord, may He be glorified and exalted." Jibreel (peace be upon him) went away, and stayed away for as long as Allaah willed that he should stay away. Then he came and said: "O Muhammad, you asked me which part of the land is worst and I said I did not know. I asked my Lord, may He be glorified and exalted, and He said: Its markets."

Narrated by Ahmad (16302); classed as saheeh by al-Albaani in Saheeh al-Targheeb (325).

4 – It was narrated that Jaabir said: The Messenger of Allaah (Peace And Blessings Of Allaah Be Upon Him) said: "I have been commanded to fight the people until they say Laa ilaaha ill-Allaah. If they say Laa ilaaha ill-Allaah, their blood and their wealth are protected from me, except in cases dictated by Islamic law, and their reckoning will be with Allaah." Then he recited: "you are only one who reminds. You are not a dictator over them" [al-Ghaashiyah 88:21,22].

Narrated by al-Bukhaari (2786) and Muslim (21)

5 – In the lengthy hadeeth which speaks of Abu Sufyaan's meeting with Heraclius, which is a hadeeth full of lessons, it says that Heraclius sent for him to come with a group from Quraysh, who were merchants trading in Syria at the time when the Messenger of Allaah (S) had made a peace treaty with Abu Sufyaan and the kuffaar of Quraysh. He summoned them to his council where he was surrounded by the great men of Byzantium, then he called them and his translator and said: Which of you is closest in kinship to this man who claims that he is a Prophet?

Abu Sufyaan said: I am closest to him in kinship.

He said: Bring him close to me, and bring his companions close and put them behind him. Then he said to his translator: Tell them that I am going to ask this one about this man, and if he lies to me they should tell me that he is lying.

Among the wise questions that Heraclius posed to Abu Sufyaan was: Did you ever accuse him of lying before he said what he said?

And at the end of the questioning, Heraclius explained to Abu Sufyaan his purpose in asking these questions. He said concerning these questions: I asked you whether you accused him of lying before he said what he said, and you said no. I knew that if he did not tell lies about people, he would not tell lies about Allaah…

Narrated by al-Bukhaari (7) and Muslim (1773).

And Allaah knows best.