1318 - ذَكَرَ اَلْفَضْلُ بْنُ شَاذَانَ اَلنَّيْسَابُورِيُّ رَحِمَهُ اَللَّهُ فِي اَلْعِلَلِ اَلَّتِي سَمِعَهَا مِنَ اَلرِّضَا عَلَيْهِ اَلسَّلاَمُ: «إِنَّ اَلصَّلاَةَ إِنَّمَا قُصِرَتْ فِي اَلسَّفَرِ لِأَنَّ اَلصَّلاَةَ اَلْمَفْرُوضَةَ أَوَّلاً إِنَّمَا هِيَ عَشْرُ رَكَعَاتٍ وَ اَلسَّبْعُ إِنَّمَا زِيدَتْ فِيهَا بَعْدُ فَخَفَّفَ اَللَّهُ عَزَّ وَ جَلَّ عَنِ اَلْعَبْدِ تِلْكَ اَلزِّيَادَةَ لِمَوْضِعِ سَفَرِهِ وَ تَعَبِهِ وَ نَصَبِهِ وَ اِشْتِغَالِهِ بِأَمْرِ نَفْسِهِ وَ ظَعْنِهِ وَ إِقَامَتِهِ لِئَلاَّ يَشْتَغِلَ عَمَّا لاَ بُدَّ مِنْهُ مِنْ مَعِيشَتِهِ رَحْمَةً مِنَ اَللَّهِ عَزَّ وَ جَلَّ وَ تَعَطُّفاً عَلَيْهِ إِلاَّ صَلاَةَ اَلْمَغْرِبِ فَإِنَّهَا لاَ تُقَصَّرُ لِأَنَّهَا صَلاَةٌ مُقَصَّرَةٌ فِي اَلْأَصْلِ وَ إِنَّمَا وَجَبَ اَلتَّقْصِيرُ فِي ثَمَانِيَةِ فَرَاسِخَ لاَ أَقَلَّ مِنْ ذَلِكَ وَ لاَ أَكْثَرَ لِأَنَّ ثَمَانِيَةَ فَرَاسِخَ مَسِيرَةُ يَوْمٍ لِلْعَامَّةِ وَ اَلْقَوَافِلِ وَ اَلْأَثْقَالِ فَوَجَبَ اَلتَّقْصِيرُ فِي مَسِيرَةِ يَوْمٍ وَ لَوْ لَمْ يَجِبْ فِي مَسِيرَةِ يَوْمٍ لَمَا وَجَبَ فِي مَسِيرَةِ أَلْفِ سَنَةٍ وَ ذَلِكَ لِأَنَّ كُلَّ يَوْمٍ يَكُونُ بَعْدَ هَذَا اَلْيَوْمِ فَإِنَّمَا هُوَ نَظِيرُ هَذَا اَلْيَوْمِ فَلَوْ لَمْ يَجِبْ فِي هَذَا اَلْيَوْمِ لَمَا وَجَبَ فِي نَظِيرِهِ إِذْ كَانَ نَظِيرُهُ مِثْلَهُ لاَ فَرْقَ بَيْنَهُمَا وَ إِنَّمَا تُرِكَ تَطَوُّعُ اَلنَّهَارِ وَ لَمْ يُتْرَكْ تَطَوُّعُ اَللَّيْلِ لِأَنَّ كُلَّ صَلاَةٍ لاَ يُقَصَّرُ فِيهَا لاَ يُقَصَّرُ فِي تَطَوُّعِهَا وَ ذَلِكَ أَنَّ اَلْمَغْرِبَ لاَ يُقَصَّرُ فِيهَا فَلاَ تَقْصِيرَ فِيمَا بَعْدَهَا مِنَ اَلتَّطَوُّعِ وَ كَذَلِكَ اَلْغَدَاةُ لاَ تَقْصِيرَ فِيهَا فَلاَ تَقْصِيرَ فِيمَا قَبْلَهَا مِنَ اَلتَّطَوُّعِ وَ إِنَّمَا صَارَتِ اَلْعَتَمَةُ مَقْصُورَةً وَ لَيْسَ تَتْرُكُ رَكْعَتَيْهَا لِأَنَّ اَلرَّكْعَتَيْنِ لَيْسَتَا مِنَ اَلْخَمْسِينَ وَ إِنَّمَا هِيَ زِيَادَةٌ فِي اَلْخَمْسِينَ تَطَوُّعاً لِيُتِمَّ بِهِمَا بَدَلَ كُلِّ رَكْعَةٍ مِنَ اَلْفَرِيضَةِ رَكْعَتَيْنِ مِنَ اَلتَّطَوُّعِ وَ إِنَّمَا جَازَ لِلْمُسَافِرِ وَ اَلْمَرِيضِ أَنْ يُصَلِّيَا صَلاَةَ اَللَّيْلِ فِي أَوَّلِ اَللَّيْلِ لاِشْتِغَالِهِ وَ ضَعْفِهِ وَ لِيُحْرِزَ صَلاَتَهُ فَيَسْتَرِيحَ اَلْمَرِيضُ فِي وَقْتِ رَاحَتِهِ وَ لِيَشْتَغِلَ اَلْمُسَافِرُ بِاشْتِغَالِهِ وَ اِرْتِحَالِهِ وَ سَفَرِهِ.
Hadith.1318 - Al-Fadl ibn Shadhan al-Naysaburi, may Allah (swt) have mercy on him, mentioned among the reasons he heard from al-Ridha 
regarding why prayers are shortened during travel.
He (Imam ) said: "The initially prescribed obligatory prayer was ten rak'ahs. The seven additional rak'ahs were later added, and Allah (swt), the Blessed and Exalted, lightened this addition for the servant due to the burden, fatigue, and preoccupation of travel. This relief was granted so that the servant would not become distracted from the essential needs of their livelihood during travel. However, the Maghrib prayer is not shortened because it was originally set as a shortened prayer.
The obligation to shorten applies to eight farsakhs (a day's journey) and no less. The reason for this is that eight farsakhs is a day’s journey for the common people, caravans, and baggage carriers, necessitating shortening for such a journey.
If the obligation were not established for a day’s journey, it would not be required for a journey of a thousand years, as every day after this day is similar to it ; if it were not obligatory for this day, it would not be obligatory for its equivalent.
Voluntary prayers during the day are omitted while traveling, but not voluntary prayers at night, because every prayer that is not shortened also maintains its voluntary aspect. Thus, the Maghrib prayer is not shortened, so neither are the voluntary prayers that follow it.
Similarly, the Fajr prayer is not shortened, so neither are the voluntary prayers preceding it. The Isha prayer (Atamah) is considered shortened, but its two rak'ahs are not omitted because they are not part of the fifty obligatory rak'ahs; rather, they are additional voluntary rak'ahs to complete the fifty.
These extra rak'ahs serve as compensation, with two voluntary rak'ahs taking the place of every rak'ah of obligation. The traveler and the sick are permitted to perform the night prayer at the beginning of the night due to their preoccupation, weakness, or to ensure they fulfil their prayers and gain rest or focus on their travel."
