حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ عَطَاءٍ الْخُرَاسَانِيِّ، أَنَّهُ سَمِعَ سَعِيدَ بْنَ الْمُسَيَّبِ، قَالَ مَنْ أَجْمَعَ إِقَامَةً أَرْبَعَ لَيَالٍ وَهُوَ مُسَافِرٌ أَتَمَّ الصَّلاَةَ ‏.‏ قَالَ مَالِكٌ وَذَلِكَ أَحَبُّ مَا سَمِعْتُ إِلَىَّ ‏.‏ وَسُئِلَ مَالِكٌ عَنْ صَلاَةِ الأَسِيرِ فَقَالَ مِثْلُ صَلاَةِ الْمُقِيمِ إِلاَّ أَنْ يَكُونَ مُسَافِرًا ‏.‏

Yahya related to me from Malik from Ata al-Khurasani that heheard Said ibn al Musayyab say, "A traveller who has decided to remainsomewhere for four nights does the prayer in full." Maliksaid, "That is what I prefer most out of what I have heard." Malik when asked about the prayer of a prisoner, said, "It is the sameas the prayer of a person who remains in one place, except if he istravelling." Translation Not Available

Book Ref: Muwatta Imam Malik Book 9 Hadith 348
Web Ref:  Muwatta Imam Malik Book 9 Hadith 20