✅پاسخ :بِإِسْنَادِهِ عَنِ الْحَسَنِ بْنِ مُحَمَّدِ بْنِ سَمَاعَةَ عَنْ سُلَیْمَانَ بْنِ دَاوُدَ عَنْ عَلِیِّ بْنِ أَبِی حَمْزَةَ قَالَ ذُکِرَ عِنْدَ أَبِی عَبْدِ اللَّهِ زَوَالُ الشَّمْسِ قَالَ فَقَالَ أَبُو عَبْدِ اللَّهِ تَأْخُذُونَ عُوداً طَوْلُهُ ثَلَاثَةُ أَشْبَارٍ وَ إِنْ زَادَ فَهُوَ أَبْیَنُ فَیُقَامُ فَمَا دَامَ تَرَی الظِّلَّ یَتَقَصَّرُ فَلَمْ تَزُلْ فَإِذَا زَادَ الظِّلُّ بَعْدَ النُّقْصَانِ فَقَدْ زَالَتْ

📚 Tahdhib, Vol. 2, p. 27

Translation: Ali ibn Abi Hamza said: The solar zenith and the time for the Dhuhr prayer were mentioned in the presence of Imam Sadiq, peace be upon him. The Imam said: Take a stick that is three spans long, and if it is larger, it will be more clear. Place that stick vertically in the ground. As long as the shadow is getting shorter, the zenith has not occurred. When the shadow begins to get longer after shortening, the solar zenith has occurred.

✅ The solar zenith, which is introduced in narrations as the beginning of the time for the Dhuhr prayer, is determined by this method that the Imam, peace be upon him, taught us. By placing a stick or a similar marker vertically in the ground, a shadow is created. At sunrise, the shadow is long, and as we get closer to noon, its length decreases. However, moments before the zenith, even though the shadow is moving eastward, its length does not decrease and remains constant. This short period of time, where the shadow's length is constant, is called 'solar stagnation,' and a reason for it is also mentioned in narrations. However, this stagnation does not exist on Friday for another reason. After this stagnation, the shadow begins to lengthen, at which time the solar zenith has occurred, and the time for the Dhuhr prayer and the main time for the Dhuhr supererogatory prayers has begun. Pay attention to the following narrations:

Imam Sadiq, peace be upon him, said: When the solar zenith occurs, the time for the Dhuhr and Asr prayers has begun, with the condition that the Dhuhr prayer must be performed first and then the Asr prayer.

📚 Al-Kafi, Vol. 3, p. 276

✅ According to the above narration, at the time of the zenith, the time for the Dhuhr and Asr prayers begins, but it is necessary to first perform the Dhuhr prayer and then the Asr prayer. For this reason, it is mentioned in narrations that the time from the zenith up to the amount of time needed to perform four rak'ahs of prayer is exclusive to the Dhuhr prayer, and the Asr prayer cannot be performed in it.

Imam Sadiq, peace be upon him, said: The wall of the mosque of the Messenger of Allah, peace and blessings be upon him, before a canopy was made for the mosque, was the height of a man. So when (from the time of the zenith) one cubit (about half a meter) was added to the shadow of the wall, which was the size of a goat's resting place, he would perform the Dhuhr prayer, and when the shadow increased by two cubits, which is twice that, he would perform the Asr prayer.

📚 Mustadrak Al-Wasa'il, Vol. 3, p. 111

✅ Regarding why, even though the time for the Dhuhr prayer begins when the solar zenith occurs, an opportunity is given until one cubit is added to the shadow of a man-high wall, pay attention to the following narration:

Imam Baqir, peace be upon him, said to Zurarah: Do you know why one cubit and two cubits were designated? I said: Why? He said: Because of the place for the obligatory prayer; you can perform the supererogatory prayer from the time of the solar zenith until the shadow (of the wall or a man-high marker) reaches one cubit (one cubit is added). So when the returning shadow reaches one cubit, you must begin the obligatory prayer and abandon the supererogatory prayer.

📚 Al-Kafi, Vol. 3, p. 288

✅ This means that this limit was set to specify the duration of the permissibility of performing the Dhuhr supererogatory prayers. If someone has not performed their supererogatory prayers by that time, they must first perform the Dhuhr prayer and then perform their supererogatory prayers as qada (missed).

Imam Sadiq, peace be upon him, said: When the solar zenith occurs, the time for the Dhuhr prayer has begun, except that before the Dhuhr prayer, there are supererogatory prayers, and you have the choice whether you want to lengthen the supererogatory prayers or perform them briefly.

📚 Al-Kafi, Vol. 3, p. 276

Mansur said: We in Medina used to measure the sun with a cubit (for prayer time). Imam Sadiq, peace be upon him, said to us: Do you want me to inform you of something clearer than this? We said: Yes, may God make us your ransom. He said: When the solar zenith occurs, the time for the Dhuhr prayer has begun, except that there is a supererogatory prayer before it, and that is up to you. If you perform the supererogatory prayers lightly and briefly, then when you are finished with the supererogatory prayers, and even if you perform the supererogatory prayers at length, you pray the Dhuhr prayer when you are finished with them.

📚 Istibsar, Vol. 1, p. 250

✅ According to the above narrations, a person who does not perform the supererogatory prayers or is a traveler for whom the daily supererogatory prayers are dropped in travel, performs the Dhuhr prayer after the zenith, and a person who performs the supererogatory prayers must be careful not to exceed its designated limit.

Other important points will be provided upon request.