ملخص الجهاز:
In other words: the general public must fast during the month of Ramadan, but the time of fasting for the excused group, known as the sick and the traveler, is other days.
According to them, before the phrase "فعدّة من أيّام أُخر," the phrase "إن أفطر" (if he breaks the fast) is implicit, so the verse is as if it were: "فمن كان منكم مريضاً أو على سفر -فأفطر-، فعدّة من أيّام أُخر" "If a sick person or a traveler breaks the fast, he can fast on other days," otherwise the time of fasting for these two groups would be the same as the general public.
The verse addresses everyone and says: It is good for all of you to fast, in the manner described in the verse; meaning the general public in the month of Ramadan, the sick and the traveler on other days when their excuse is removed, and the elderly in the month of Ramadan, although fasting for the fourth group is not obligatory due to the permission being replaced by (expiation/kaffarah).
2. Ibn Majah al-Qazwini and Abu Dawud narrate in their Sunan from Abd al-Rahman bin Awf that the Prophet (peace be upon him and his family) said: »صائِمُ رَمضانٍ فِى السَّفرِ كالمُفْطِرِ فى الحَضَر«: A fasting person on a journey is like one who breaks the fast while at home(5).
Narrations from the Imams of the Ahl al-Bayt (peace be upon them) regarding the obligation of breaking the fast for the traveler are also abundant, and those interested can refer to the book "Wasa'il al-Shia, Vol. 7".