Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
malik:9-13Mālik > Ibn Shihāb > Sālim b. ʿAbdullāh from his father

Yahya related to me from Malik from Ibn Shihab from Salim ibn Abdullah that his father rode to Rim and shortened the prayer on the journey. Malik said, "That was about four mail-stages." (approximately forty-eight miles).  

مالك:٩-١٣وَحَدَّثَنِي عَنْ مَالِكٍ عَنِ ابْنِ شِهَابٍ عَنْ سَالِمِ بْنِ عَبْدِ اللَّهِ عَنْ أَبِيهِ

أَنَّهُ رَكِبَ إِلَى رِيمٍ فَقَصَرَ الصَّلاَةَ فِي مَسِيرِهِ ذَلِكَ قَالَ مَالِكٌ وَذَلِكَ نَحْوٌ مِنْ أَرْبَعَةِ بُرُدٍ