I wanted to clear out a misconception by some non-Muslims, unfortunately they try to discredit the Quran by cheap shots and one of them is claiming that the Quran contradicts Arabic Grammar!
It is very funny to me because it is as someone saying there are tajweed mistakes in the Quran; the idiot wouldn't know what s/he is talking about – we all know tajweed is based solely and exclusively on the Quran.
Tajweed and Arabic grammar relate to the Quran in the same way but it is more obvious regarding tajweed because tajweed is exclusively for the Quran, meaning you can't use tajweed on poems or any other form of Arabic text, however Arabic grammar is used everywhere in Arabic and that's where the confusion came from.
Like Tajweed, Arabic grammar didn't exist before the Quran, in fact their rules were formed and adjusted many years after revealing the Quran and based on the Quran. The first Arabic grammar books were written by Muslims (years after the Quran) based mainly on the Quran, secondary sources were old Arabic literature and mainly poems.
The companions memorized the Quran with it's tajweed that they never learned it's rules because it didn't exist at their time, meaning they memorized it in the same way the prophet pronounced it to them, they didn't know that after noon as-sakinah they should make idgham, ikhfa', iqlab or idh-har, these phrases didn't have the meaning that we know of today, however the companions applied these rules not knowing these phrases becase they memorized the pronouciation in the same way they heard it from the prophet. Later muslim scholars analyzed how these words are pronounced and came up with tajweed rules that we know today.
The same thing happened to Arabic grammar it didn't exist at the time the Quran was revealed, Arabs spoke Arabic perfectly, however after many non arabs became Muslims and started reciting the Quran wrongly that's when grammar was formed and that's even when dots were introduced to Arabic - can you believe that? The Arabic letters ba, ta, tha were written in the same way without dots, however when non arabs didn't know how to read the Quran because they don't know the difference between these letters; muslim scholars introduced these dots to help them out. Later muslim scholars introduced tashkeel (damma, fatha, kasra, etc.) so these non arabs can recite the Quran correctly, you see how basic Arabic grammar was at the time the Quran was revealed, there was absolutely no grammar rules, it is like an illiterate speaking English does s/he need grammar to be able to speak English correctly? No, because it is their mother tongue; however for a foreigner studying grammar helps a lot.
If you give me or any native Arabic speaker an Arabic text without tashkeel; we can read it perfectly and easily, however for a non arab native reading Arabic without tashkeel is very hard. Our level in Arabic compared to the companions and earlier Arabs is like non-Arab natives level compared to us, meaning if you give me Arabic text without dots (ba is written exactly like ta and tha) it would be very hard for me to read, however for the companions and early arabs that was an easy task. This is why the first miracle of the Quran was to challenge Arabs in Arabic, they were great poets and the Quran was revealed to an illiterate who challenged all Arab geniuses in their own game.
Anyways, as you see the main source for Arabic grammar is the Quran, secondary sources are old poems. If an Arabic grammar rule contradicts a verse in the Quran that means Arabic grammar is adjusted and its rules are changed to meet the Quran, meaning Arabic grammar is wrong not the Quran, because Arabic grammar is based on the Quran not vice versa.
This would sound very familiar for anyone who knows basics of tajweed, there are verses in the Quran that don't match the general rules of tajweed, an amature student would read these verses wrongly thinking that s/he knows tajweed rules very well, however when s/he recites in front of a Qari, s/he will point his/her mistake and tell him/her this is how correct tajweed is performed, which is an exception to the general rule this amature knows.
May Allah guide us all to the straight path.