Hadith 31-165

وَبِهذَا الإِسناد عَنْ جَعْفَرِ بْنِ بْنِ مُحَمَّدعَلَيْهِمَا السَّلاَمُ قالَ: سُئِلَ مُحَمَّدِ بْنِ عَلِى‏عَلَيْهِمَا السَّلاَمُ عَنِ الصَّلاة فِي السَّفَر، فَذَكَرَ أَن أَباهُ‏ عَلَيْهِ السَّلامُ كانَ يُقَصِّرُ الصَّلاةَ فِي السَّفَرِ.

According to the same documentation, on the authority of Ja’far ibn Muhammad (a.s.) that Muhammad ibn Ali (a.s.) was questioned about praying on a journey. He (a.s.) replied, “My father (a.s.) shortened his prayers while he (a.s.) was on a journey.”