Hadith 4:135
'Abdah narrated to us, from Sa'id, from Qatadah, from 'Ali (may Allah have mercy on him), who said: If Ramadan reaches him while he is a resident, then he travels, he should fast.
حدثنا عبدة عن سعيد عن قتادة عن علي رحمه الله قال إذا ادركه رمضان وهو مقيم ثم سافر فليصم