(1) باب صَلاَةِ الْمُسَافِرِينَ وَقَصْرِهَا
'A'isha, the wife of the Messenger of Allah (ﷺ), reported:
The prayer was prescribed as two rak'ahs, two rak'ahs both in journey and at the place of residence. The prayer while travelling remained as it was (originally prescribed), but an addition was made in the prayer (observed) at the place of residence.
Reference: Sahih Muslim 685 a
In-book reference: Book 6, Hadith 1
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1458