The whole premise of the necessity of Hadis corpus is based on two misconceptions:
1- Qala Rasullullah- the Rasool said this that or the other…. And
2- That Quran can not be understood without the help of hadis corpus (apocrypha)
The first point to remember is that hadis is not the direct speech of the Rasool. What ever is given in hadis is a reported speech through a series of lot of reporters. There is inevitably a huge question of time gap and locations of these various reporters viz a viz the Rasool.
What is not realized is that a Rasool is only a Rasool in the context of his Risaalaah—the Book. In the case of Muhammad, the Book is obviously the Quran. As is Ingeel for Jesus, Toraat for Moses, Zaboor for ….and so on.
In the Risaalaah of Muhammad; what ever he was instructed to say (21-45 etc) is listed as “qul”---That is, you say, declare, announce etc and they all add up to about two hundred and sixty. The last three in the book, for example also being in that category of Qul.
Therefore what begins in the Hadis as Qala Rasullullah cannot by any stretch of imagination be taken as the Quls of Quran. This is categorically denied by the Quran, “-----and they say ‘that is from God (wahi-inspiration) but it is not from God. It is they who tell a lie against God, and well they know it” 3-78
The second argument that the Quran can not be understood without the apocrypha of hadis amazes even an ordinary student of Quran, as one knows that the Quran stresses vehemently that IT explains itself by repeating itself over and over again in order to elaborate an issue.
The insistence by some people upon external corpus, is an obvious example of paddling the religious wares for vested interests to say the least (one being the survival of the mother church). Quran is well aware of it and warns us-----“ then woe to those who write the book (apocrypha) with their own hands and then say ‘this is from god’ to traffic with it for miserable price!” 2-79. Not to mention Irtaza’s oft quoted 39-23--- the Quran is the Best hadis”