✅Answer:

1 From Raja' ibn Abi al-Dahhak in a hadith, he said: 'When the sun passed its meridian (i.e., at the time of the Zuhr prayer), Imam Rida (peace be upon him) would renew his 'wudu' and stand and pray six 'rak'ahs' (from the supererogatory prayers of Zuhr) and in the first 'rak'ah' of it, he would recite 'al-Hamd' and 'Qul ya ayyuha al-Kafirun' and in the second, 'al-Hamd' and 'Qul huwa Allahu Ahad' and in the other four 'rak'ahs', he would also recite 'Qul huwa Allahu Ahad' in each 'rak'ah', and he would say the 'taslim' after every two 'rak'ahs' and he would perform 'qunut' in the second of them before the 'ruku'' and after the recitation, then he would call the 'adhan' and pray two more 'rak'ahs' (from the supererogatory prayers of Zuhr) and then he would call the 'iqamah' and pray the Zuhr prayer, and when he said the 'taslim' of the prayer, he would glorify Allah and praise Him and magnify Him and declare His oneness as much as Allah willed, and then he would perform a 'sajdat al-shukr' (prostration of gratitude) in which he would say a hundred times: 'Thanks be to Allah' and when he raised his head, he would stand up and pray six 'rak'ahs' (from the supererogatory prayers of Asr) and in each 'rak'ah' he would recite 'al-Hamd' and 'Qul huwa Allahu Ahad' and he would say the 'taslim' after every two 'rak'ahs' and he would perform 'qunut' in the second of every two 'rak'ahs' before the 'ruku'' and after the recitation, then he would call the 'adhan' and pray two 'rak'ahs' (the remaining from the supererogatory prayers of Asr) and he would perform 'qunut' in the second 'rak'ah' of it, and when he said the 'taslim', he would call the 'iqamah' and pray the Asr prayer, and he would sit in his place of prayer and glorify Allah and praise Him and magnify Him and declare His oneness as much as Allah willed, and then he would perform a 'sajdat al-shukr' and in it he would say a hundred times: 'Praise be to Allah'.

📚'Uyun Akhbar al-Rida (peace be upon him), Vol. 2, p. 181

📚Al-Tahdhib, Vol. 3, p. 18

2 عن عمربنِ أُذينة عن رَهْط مِنْهُمُ الْفُضَيْلُ و زرارة عن أَبِي جَعْفَر أَنَّ رَسُولَ اللَّهِ جَمَعَ بَيْنَ الظُّهْرِ وَ الْعَصْرِ بِأَذَانٍ وَ إِقَامَتَيْنِ وَ جَمَعَ بَيْنَ الْمَغْرِبِ وَ الْعِشَاءِ بِأَذَانٍ وَاحِدٍ وَ إِقَامَتَيْن

Imam Baqir (peace be upon him) said: 'The Messenger of Allah (peace be upon him and his family) combined the Zuhr and Asr prayers with one 'adhan' and two 'iqamahs' and also combined the Maghrib and 'Isha' prayers with only one 'adhan' and two 'iqamahs'.

📚Al-Kafi, Vol. 3, p. 287

3 محمدبن حكيم قال سَمِعْتُ أَبَاالْحسن يَقُولُ الْجَمْعُ بَيْنَ الصَّلَاتَيْن إِذَا لَمْ يَكُنْ بَيْنَهُمَا تَطَوُّعٌ فَإِذَا كَانَ بَيْنَهُمَا تَطَوُّعٌ فَلَا جَمْع

Muhammad ibn Hakim said: I heard Imam Abu al-Hasan (peace be upon him) say: 'Combining between two prayers is when there are no supererogatory prayers between them, so if a supererogatory prayer is performed between them, it is not a combination (it is not considered a combination).'

✅The permissibility of combining between the two prayers of Zuhr and Asr and the prayers of Maghrib and 'Isha', meaning performing them in one time and together, has been mentioned in many narrations.

According to the third narration, this combination is considered a combination only if the person, in addition to performing them at one time and together, does not perform a supererogatory prayer between these two prayers, and in the case of combining two prayers, according to many narrations, including the second hadith, both the 'adhan' and the 'iqamah' are called for the first prayer and only the 'iqamah' is called for the second prayer, and in fact, they are performed with one 'adhan' and two 'iqamahs'.

✅In Shi'a narrations, pilgrims are commanded to combine their Zuhr and Asr prayers on the day of 'Arafah and their Maghrib and 'Isha' prayers in Muzdalifah, and also a woman with a chronic flow of blood in some situations, and to achieve this combination, they should not perform a supererogatory prayer between the two prayers and they can make up for the supererogatory prayers later if they wish. However, in normal circumstances, like the first narration, a person can perform their supererogatory prayers between the Zuhr and Asr prayers and the Maghrib and 'Isha' prayers, but in this case, the prayers are not performed as a combination, and if they want the reward of the 'adhan' for the Asr and 'Isha' prayers, they also call the 'adhan' for them, even if they performed them at one time, because the supererogatory prayers in between prevented them from being combined, and therefore, performing a supererogatory prayer between two prayers, in the case of performing the prayers together, is not a problem and only negates their being combined.