عَنْ مُوسَى بْنِ سَلَمَةَ قَالَ: كُنَّا مَعَ ابْنِ عَبَّاسٍ بِمَكَّةَ، فَقُلْتُ: إِذَا كُنَّا مَعَكُمْ صَلَّيْنَا أَرْبَعًا، وَإِذَا رَجَعْنَا إِلَى رِحَالِنَا صَلَّيْنَا رَكْعَتَيْنِ، قَالَ: سُنَّةُ أَبِي الْقَاسِمِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ
Musa bin Salamah says: We were in Makkah with Sayyiduna Abdullah bin Abbas (may Allah be pleased with him). I said: When we are with you, we perform four rak‘ahs of prayer, and when we return to our residences, we perform two rak‘ahs (shortened prayer). Sayyiduna Abdullah said: This is the Sunnah of Abu al-Qasim (peace and blessings be upon him).