Surah Ghafir, Ayah 6

One of the Attributes of the Disbelievers is That they dispute theAyat of Allah -- and The Consequences of that Allah tells us that noone rejects or disputes His signs after clear proof has come,

إِلاَّ الَّذِينَ كَفَرُواْ

(but those who disbelieve), i.e., those who reject the signs of Allah and His proof and evidence.

فَلاَ يَغْرُرْكَ تَقَلُّبُهُمْ فِى الْبِلاَدِ

(So let not their ability of going about here and there through the land deceive you!) means, their wealth and luxurious life. This is like the Ayah:

لاَ يَغُرَّنَّكَ تَقَلُّبُ الَّذِينَ كَفَرُواْ فِى الْبِلَـدِ - مَتَـعٌ قَلِيلٌ ثُمَّ مَأْوَاهُمْ جَهَنَّمُ وَبِئْسَ الْمِهَادُ

(Let not the free disposal (and affluence) of the disbelievers throughout the land deceive you. A brief enjoyment; then, their ultimate abode is Hell; and worst indeed is that place for rest.) (3:196-197)

In verse 4, it was said: مَا يُجَادِلُ فِي آيَاتِ اللَّـهِ إِلَّا الَّذِينَ كَفَرُ‌وا (No one quarrels about the verses of Allah, except those who disbelieve.). This verse declares quarreling in the matter of the Qur'an an act of kufr (disbelief). And the Holy Prophet ﷺ has said: اِنَّ جِدَالأ فِی القُراٰنِ کُفرُ (Surely, quarreling (jidal) in the Qur'an is kufr.' (Reported by al-Baghawi, al-Baihaqi in ash-Shu'ab from Sayyidna Abu Hurairah ؓ ; and reported by Abu Dawud and al-Hakim who has rated it as 'Sahib- Mazhari)

It appears in Hadith that, on a certain day, the Holy Prophet ﷺ heard two persons quarreling about some verse of the Qur'an. He got angry, and came out with his blessed face showing the signs of anger. He said, 'communities before you were ruined because they had started quarreling in the matter of the Book of Allah.' (Reported by Muslim from ` Abdullah Ibn ` Amr Ibn Shu'aib - Mazhari)

Here the ‘signs of God’ (ayatullah) means the arguments advanced to establish the veracity of the divine mission. Those who are not serious with regard to God, raise irrelevant points in these arguments and thus create doubt in the minds of the people that this call is not a true call but only a flight of imagination on the part of the preacher. Bickering of this kind constitutes a very great sin. However, in the present world of trial, those who indulge in bickering are given respite only temporarily and for a fixed period. Thereafter, they are destined to face the same miserable fate as was faced by the communities of Noah, ‘Ad, Thamud, etc. Those who considered themselves great were belittled, while those who were considered of no account by others were treated as great before God.