5. This implies two things: First, Allah sent down His message in the language of the people from among whom a Prophet was raised so that they might not have any excuse left that they could not understand the language of the message. Secondly, this ruled out the presumption that a Messenger was ever given the message in a different language merely for the sake of a miracle. For Allah considered it more important to make the people understand the message and guide them rightly than to satisfy their curiosity. Obviously the purpose could best be served only if the message was sent down to them in their own language by their Prophet and not in any other.
6. That is, although the Messenger conveys the message in the mother tongue of the people, which is understood by everyone of them, yet all of them are not guided aright. This happens because of the fact that all of those who understand a message do not necessarily accept it. For it is entirely with Allah to show guidance by means of His message to anyone He wills and to let go astray anyone in spite of it.
7. As Allah is All-Powerful, no one is able by oneself to get guidance or to go astray, for none is completely independent but is under the power of Allah. But as He is All-Wise, He does not use His power blindly so as to show guidance to anyone He wills and to let go astray anyone He desires without rhyme or reason. In fact, the one who gets guidance from Him gets it on merit and the one who is let go astray is deprived of guidance because he himself deliberately chooses deviation.