Al-Jawab Billahi At-Taufeeq (the answer with Allah’s guidance)
The reason for silent recital in Zuhr and Asr but audible recital in Fajr, Maghrib and ‘Isha prayers:
There is much wisdom in prayer at the times of Zuhr and ‘Asr, and an audible recital in Fajr, Maghrib and ‘Isha prayers. At the hours of Fajr, Maghrib and ‘Isha people are normally unoccupied, not given to speaking and not moving about much. They are quiet resting. At these hours they have less thought on mind and are not much worried either. Therefore, the recital at these hours is more effective on the hearts which are not bunkerd with thoughts and worries. The ears are more receptive because they do not have to hear other things. Anything spoken at is passed on directly to the heart. By the ears;it is then well received and effective. This effect is confirmed by the Quran too.
“Verily, the rising by night (for Tahajjud prayer) is very hard and most potent and good for
governing (the soul), and most suitable for (understanding) the Word (of Allah).” (73:6)
It is also confirmed by the experience that a sweet voice, the singing of the birds and the beat of drums is well received by the hearts in the night than during the daytime. Thus, an audible recital is adopted at hours when it is more effective.
In the same way, an inaudible recital of the Quran at the hour of Zuhr and ‘Asr is not without reason. There is a lot of noise in the markets and homes during daytime. Hearts are occupied in many tasks and there is commotion everywhere so that it is difficult to pay attention to anything well. That is why the recital at these hours is silent or inaudible. It is this very thing that Allah Ta’ala has referred in the Quran when He says,
“Verily, there is for you by day prolonged occupation with ordinary duties.” (73:7)
One cannot concentrate well during this time but at night the heart is synchronized with the tongue and the tongue with the ear. This is why it is Sunnah to recite a longer passage of the Quran in the Fajr prayer compared to recital in other prayers. The Prophet (Sallallahu Alaihi Wasallam) used to recite 60 to a 100 verses in the Fajr prayers. The heart is restful after waking up from sleep and it is wise that the first words conveyed to the heart through the words of Allah in which there is good and blessings for man. At this hour those words cast a deep impression on the heart without any interruption and make a home there.
(The wisdom behind the commands of Islam Pg. 103,104,105)
And Only Allah Ta’ala Knows Best.
Moulana Qamruz Zaman