Sunan an-Nasa'i 602
سنن النسائي#602SahihIt was narrated from Ibn 'Abbas that the Prophet (ﷺ) used to pray in Al-Madinah combining two prayer. Joining Zuhr and 'Asr, and Maghrib and 'Isha', when there was no fear nor rain. It was said to him:"Why?" He said: "So that there would not be any hardship on his Ummah
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu Ghuddah-
Zubair Ali ZaiSahih Muslim
In-book reference: 6:109