It was narrated that Ibn ‘Abbas (رضي الله عنه) said:

The Prophet (ﷺ) put Zuhr and ‘Asr together in Madinah, when he was not travelling and there was no fear. I (the narrator) said: O Abul-'Abbas, why did he do that? He said: He did not want to make things difficult for anyone of his ummah.