Sunan an-Nasa'i 2302
سنن النسائي#2302SahihHamzah bin 'Amr narrated that he asked the Messenger of Allah, and he wsa a man who used to fast while traveling. He said:"If you wish then fast, and if you wish then fast, and if you wish then do not fast
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiHasan
In-book reference: 22:213