قُلْتُ لَهُ أَ رَأَيْتَ مَنْ قَدِمَ بَلْدَةً إِلَى مَتَى يَنْبَغِي لَهُ أَنْ يَكُونَ مُقَصِّراً وَ مَتَى يَنْبَغِي لَهُ أَنْ يُتِمَّ قَالَ إِذَا دَخَلْتَ أَرْضاً فَأَيْقَنْتَ أَنَّ لَكَ بِهَا مُقَاماً عَشَرَةَ أَيَّامٍ فَأَتِمَّ الصَّلَاةَ وَ إِنْ لَمْ تَدْرِ مَا مُقَامُكَ بِهَا تَقُولُ غَداً أَخْرُجُ أَوْ بَعْدَ غَدٍ فَقَصِّرْ مَا بَيْنَكَ وَ بَيْنَ أَنْ يَمْضِيَ شَهْرٌ فَإِذَا تَمَّ لَكَ شَهْرٌ فَأَتِمَّ الصَّلَاةَ
“I once asked abu Ja‘far (a.s.), about a man who returns home from a journey. To what time is he required to perform his Salah (prayer) as reduced, and when is he required to perform his Salah (prayer) as complete? He (the Imam) said, ‘If you enter a land and you become certain of staying there for ten days, then perfo