There are some who claim that the Quran is incomplete, that the Quran does not explain all things, and that certain issues and subjects must be consulted from other sources to get a clearer picture, such as going to the hadiths and tafsir. An example would be the prayers, to fully understand and learn on how to pray one must consult the sunnah of the prophet which is to be found in the hadiths, hence critics of the Quran argue that this proves the Quran is incomplete.
After the critic makes this argument he claims that this infact disproves the Quran because the Quran says that it fully explains everything, hence why should Muslims have to consult other sources if the Quran says it has already explained everything in vast detail and so on, for instance here are the verses they quote:
006.114 YUSUFALI: Say: "Shall I seek for judge other than Allah? - when He it is Who hath sent unto you the Book, explained in detail." They know full well, to whom We have given the Book, that it hath been sent down from thy Lord in truth. Never be then of those who doubt.
010.024 YUSUFALI: The likeness of the life of the present is as the rain which We send down from the skies: by its mingling arises the produce of the earth- which provides food for men and animals: (It grows) till the earth is clad with its golden ornaments and is decked out (in beauty): the people to whom it belongs think they have all powers of disposal over it: There reaches it Our command by night or by day, and We make it like a harvest clean-mown, as if it had not flourished only the day before! thus do We explain the Signs in detail for those who reflect.
030.028 YUSUFALI: He does propound to you a similitude from your own (experience): do ye have partners among those whom your right hands possess, to share as equals in the wealth We have bestowed on you? Do ye fear them as ye fear each other? Thus do we explain the Signs in detail to a people that understand.
Many more verses could be shown but the point is clear, that the Quran affirms that it is indeed a book that explains things and signs in details.
So now does the Quran get disproved when Muslims go to hadiths or tafsirs? No, not at all, because the one who argues such an argument is infact being dishonest! The one who is making such an argument forgot to quote these other important verses which gives you the big picture:
004.080 YUSUFALI: He who obeys the Messenger, obeys Allah: But if any turn away, We have not sent thee to watch over their (evil deeds).
So as you can see Muslims are commanded to obey the prophet Muhammad, and this verse explains the importance of obeying the prophet, that obeying the prophet is infact like obeying God since the prophet is conveying what God commanded. Hence when Muslims consult the hadiths and the sunnah of the prophet for explanations this doesn't disprove the Quran, rather it is following the Quran's command! Because the Quran commands us to obey the prophet.
Here is another verse that completely crushes this argument and exposes the critic's dishonesty:
2: 151- Similarly (to complete My Blessings on you) We have sent among you a Messenger (Muhammad SAW) of your own, reciting to you Our Verses (the Qur'ān) and sanctifying you, and teaching you the Book (the Qur'ān) and the Hikmah (i.e. Sunnah, Islāmic laws and Fiqh - jurisprudence), and teaching you that which you used not to know.
As you can see here the Quran says that the prophet Muhammad teaches people the book! So when people consult the hadiths where they find the prophet Muhammad teaching us about the Quran this doesn't disprove the Quran as being incomplete, rather it is following the Quran! The Quran is indeed complete, because it tells us that we should obey the prophet, and that the prophet teaches the book, so when we learn the book and learn certain things from another source such as the hadith it is following the Quran's command and it shows the Quran is indeed complete and explains everything for us! Because if we don't understand something from the Quran, then the Quran sorts this problem out for us by commanding us to go to the prophet! Hence it indeed explains everything for us.
Remember the previous verse I quoted, which stated that obeying the prophet is like obeying God, hence when one takes knowledge and wisdom about the Quran from the prophet it is like taking it from God since the prophet got his wisdom and knowledge about the Quran from God!
So therefore these verses expose the critics complete dishonesty, because they quote out of context, they only quote the verses saying the Quran explains things in details etc, yet they don't quote the verses where the Quran also explains to us that we should infact go to the prophet to also understand the Quran and its rulings and teachings!
Had the Quran not instructed us to obey the prophet and consult him for explanations and rulings then one could say the Quran is incomplete, yet the Quran explains to us that we should consult the prophet who teaches the book so that we may understand it better, hence the Quran explains everything for us.
And here is another verse:
- O you who believe! Obey Allāh and obey the Messenger (Muhammad SAW), and those of you (Muslims) who are in authority. (And) if you differ in anything amongst yourselves, refer it to Allāh and His Messenger (SAW), if you believe in Allāh and in the Last Day. That is better and more suitable for final determination.
The Quran commands us to obey those in authority, such as the scholars and the ones of knowledge, hence when we don't understand something or need to have something explained to us then we should refer to these people in authority about the matter. And the verse goes on to say that if we have any differences amongst ourselves then we should resolve this issue by first going to Allah, which means going to the Quran to see what Allah commands, and then secondly we should go to the prophet which means his sunnah which is to be found in the hadiths and see what it says. Hence in this verse the Quran is giving the sunnah of the prophet which is to be found in the hadiths a very high ranking authority! Only second to the Noble Quran.
So how can someone claim the Quran is incomplete when the Quran strictly commands us to refer to the prophet for guidance and instruction? How can someone claim the Quran is incomplete when it grants such a high authority for the prophets teachings and guidance?
This verse basically sums it all up, that Muslims have two sources to refer to for explanations, one which is the Quran which comes first, and 2 is the Sunnah of the prophet, and after this we can go to the ones in authority, the learned scholars and learn from them since the scholars are the inheritors of the prophets as the prophet Muhammad said.
Now offcourse a critic will not quote this for you, the critic wants to deceive and fool you, quoting part of the Quran and leaving the other half which explains the issue for you!
So in conclusion the Quran is indeed a complete book which explains everything for us, referring to the hadiths and works of scholars does not disprove this fact since the Quran commanded us to do so!