Quran’s claim about no contradictions is in accordance with the high caliber of its subject matter. Following is from the note on Quran verse 4:82 in Al-Bayan:
The implication is that if they had reflected on the Qur’an, they would never have been doubtful about the prophethood of Muhammad (sws). This is because it is not possible that for years a person should give speeches on a variety of topics in different situations and circumstances and when these speeches are compiled from the beginning to the end they form such a harmonious and congruous discourse that it has no contradiction of views and does not reflect any effects of mood change of the speaker and also does not depict any revision or change of views. Only the Qur’an has this characteristic and this is clear evidence to its divine origin. Imam Amin Ahsan Islahi writes:
So sound and well-knit is every idea of the Qur’an, both in its principle and in the corollaries of these principles that even the formulae of Arithmetic and Geometry are not as sound and well-knit. So connected and linked are the beliefs it teaches that if any one of these beliefs is removed, the whole chain and sequence falls apart. The rituals of worship and other directives it gives spring from beliefs just as branches spring from a stem. The deeds and morals it instructs its followers to adopt emanate from the principles in a manner that natural and obvious consequences emanate from something. The system of life which comes into existence as a result of its overall teaching is like that of a lead-cemented wall in which each and every brick is attached to the other in a manner that it cannot be separated from the other except if a gap is created in the whole structure