The Reason for Shortening Prayers During Travel

ذَكَرَ الْفَضْلُ بْنُ شَاذَانَ النَّيْسَابُورِيُّ رَحِمَهُ اللَّهُ فِي الْعِلَلِ الَّتِي سَمِعَهَا مِنَ الرِّضَا ع- إِنَّ الصَّلَاةَ إِنَّمَا قُصِرَتْ فِي السَّفَرِ لِأَنَّ الصَّلَاةَ الْمَفْرُوضَةَ أَوَّلًا إِنَّمَا هِيَ عَشْرُ رَكَعَاتٍ وَ السَّبْعُ إِنَّمَا زِيدَتْ فِيهَا بَعْدُ فَخَفَّفَ اللَّهُ عَزَّ وَ جَلَّ عَنِ الْعَبْدِ تِلْكَ الزِّيَادَةَ لِمَوْضِعِ سَفَرِهِ وَ تَعَبِهِ وَ نَصَبِهِ وَ اشْتِغَالِهِ بِأَمْرِ

Hadith.1318 - Al-Fadl ibn Shadhan al-Naysaburi, may Allah (swt) have mercy on him, mentioned among the reasons he heard from al-Ridha (as) regarding why prayers are shortened during travel. He (Imam (as)) said: "The initially prescribed obligatory prayer was ten rak'ahs. The seven additional rak'ahs were later added, a

لَهُ‌ مَتَى فُرِضَتِ الصَّلَاةُ عَلَى الْمُسْلِمِينَ عَلَى مَا هِيَ الْيَوْمَ عَلَيْهِ فَقَالَ بِالْمَدِينَةِ حِينَ ظَهَرَتِ الدَّعْوَةُ وَ قَوِيَ الْإِسْلَامُ وَ كَتَبَ اللَّهُ عَزَّ وَ جَلَّ عَلَى الْمُسْلِمِينَ الْجِهَادَ زَادَ رَسُولُ اللَّهِ ص فِي الصَّلَاةِ سَبْعَ رَكَعَاتٍ فِي الظُّهْرِ رَكْعَتَيْنِ وَ فِي الْعَصْرِ رَكْعَتَيْنِ وَ فِي الْمَغْرِبِ رَكْعَةً وَ فِي الْعِشَاءِ الْآخِرَةِ رَكْعَتَيْنِ وَ أَقَرَّ ا

Hadith.1319 - Sa'id ibn al-Musayyib asked Ali ibn al-Hussain (as), "When was the prayer made obligatory upon the Muslims in the form it is today?" He (as) replied: "In Medina, when the call (to Islam) became manifest, Islam was strengthened, and Allah (swt), the Mighty and Majestic, prescribed jihad upon the Muslims. T