The Adhan (calling for prayer) is Sunnah of the Prophet (saws), but it is mentioned in the Holy Quran, as the Adhan is the proclaiming the call for the prayer.
(… اتَّخَذُوهَا هُزُوًا وَلَعِبًا …) (…they take it in ridicule and amusement.…): They say: What are these words? Although the call to prayer when it sounds, it rests the heart of the believer and the non-believer as well, of course the voice of the caller to prayer must be soft and beautiful to have an affect of the listeners, indeed the Prophet (saws) when Abdullah bin Zaid told him about his dream of Adhan, the Prophet (saws) said to him:
“It is a genuine vision, if God will; so get up along with Bilal, and when you have taught him what you have seen let him use it in making the call to prayer, for he has a nicer voice than you have.”[1]
Hence, the voice of the one who calls for prayer should be nice in parallel with the words of Adhan, moreover the Prophet (saws) said about them:
The Mu’adhdhins will have the longest necks on the Day of Resurrection.[2]
Because the words of Adhan are great, that is, to say (Allahu Akbar) means that Allah (swt) is greater than all your worries, troubles and affairs in this world.
( ذَٰلِكَ بِأَنَّهُمْ قَوْمٌ لَّا يَعْقِلُونَ… ) (…That is because they are a people who do not use reason.): The source of the Arabic word of (use reason) (Ya’qel) is to tie the camel’s foot with a rope to restrain it. Some people want to release freedom of thought as they wanted without controls according to their whims and this is in contrary to using the reason, the mind prevents thought from being a justification for passion, which is deviation from the right path, and the mind tells you that you should not harm your neighbors, steal from others’ money, kill or transgress, so Allah (swt) addresses them by reason; because they are a people who do not comprehend, that is, their mind does not prevent their desires, for reason makes a person not commit evil; Because he thinks of the punishment and the good reward, and a sane person does not glorify his desires instead of Allah (swt).
[1] Sunan Abi-Dawood: Book of Prayer, Chapter: How the Adhan is Performed, Hadith No. 499.
[2] Sahih Muslim: Book of Prayer, Chapter: The Virtue Of the Adhan, And The Shaitan Flees When He Hears It, Hadith No. 387.