(1) باب صَلاَةِ الْمُسَافِرِينَ وَقَصْرِهَا
Ibn 'Abbas reported:
Allah has prescribed the prayer through the word of your Prophet (ﷺ) as four rak'ahs when resident, two when travelling, and one when danger is present. (PT)
Reference (PT): Sahih Muslim 687 a (PT)
In-book reference (PT): Book 6, Hadith 6 (PT)
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1463 (PT)