مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3374
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn ‘Abbas (رضي الله عنه) that The Messenger of Allah (ﷺ) put Zuhr and ‘Asr together, and Maghrib and ‘Isha' together, when travelling and when not travelling.
Musnad Ahmad 3397A saheeh hadeeth; this is a da'eef isnad because Laith is da