What is the ruling on making up the fast of the first day of Ramadan for those who come from a country where the sighting of the crescent has been confirmed to a country where it has not been confirmed, and is the fast of those who fasted valid?

Firstly: The moon sighting for the new crescent differs, and each country has its own sighting, and one is not obligated to fast based on the moon sighting in another country.

Secondly: Whoever entered Ramadan in one country is obligated to fast with its people, as Allah Almighty says: (So whoever among you sights the moon of the month, let him fast it). This includes one who moved to a country where the beginning of the month has not yet been announced.

Thirdly: The rule is that the traveler follows the country he moved to in completing the month. So, if the people of the second country complete thirty days of fasting, he fasts with them, even if this leads to him fasting thirty-one days. Al-Nawawi mentioned in "Al-Majmu'" and Ibn Hajar Al-Haytami in "Tuhfat Al-Muhtaj" that the traveler agrees with the people of the country he moved to regarding fasting and ending it. Therefore, he is obligated to fast with them even if what he has fasted amounts to thirty-one days.