مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2063
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn ‘Abbas said: The Messenger of Allah (ﷺ) enjoined prayer when travelling and not travelling. Just as (nafl) prayers are offered when not travelling, before and after (the obligatory prayer), they should also be offered when travelling, before and after (the obligatory prayer).
Musnad Ahmad 2064lts isnad is hasan]