The Unity of Muslims in Fasting and Breaking the Fast is a Shari'ah Requirement

Question: The Imam of Al-Azhar spoke at the beginning of the blessed month of Ramadan about the importance of unifying the sighting of the crescent moon in the Islamic world and called for a gathering of Muslim scholars to establish this. What is your Eminence’s view on this and its feasibility?

Answer: There is no doubt that the unity of Muslims in fasting and breaking the fast is a good and desirable matter for the souls, and it is required by the Shari'ah where possible, but there is no way to achieve this except through two things:
The first is that all Muslim scholars must abandon reliance on astronomical calculations, just as the Messenger of Allah (peace and blessings be upon him) abandoned it and the Salaf of the Ummah abandoned it, and they must act based on the sighting or completing the count, as the Messenger of Allah (peace and blessings be upon him) explained in the authentic hadiths. Shaykh al-Islam Ibn Taymiyyah mentioned in the Fatawa, vol. 25, pp. 132-133, the consensus of the scholars that it is not permissible to rely on calculations to establish fasting, breaking the fast, and the like. Al-Hafiz transmitted in al-Fath, vol. 4, p. 127, from al-Baji: "The consensus of the Salaf on not giving weight to calculations, and that their consensus is a proof against those who came after them."
The second matter is that they must commit to relying on the establishment of the sighting in any Islamic state that operates by the Shari'ah of Allah and adheres to its rulings. So whenever the sighting of the crescent moon is established there by the Shari'ah evidence, whether for its entry or exit, they should follow them in that, acting in accordance with the saying of the Prophet (peace and blessings be upon him): , and his saying (peace and blessings be upon him): "We are an unlettered nation; we do not write and we do not calculate. The month is like this, like this, and like this," and he gestured with his hand three times and folded his thumb on the third, and gestured with all his fingers, meaning by that (peace and blessings be upon him) that the month may be twenty-nine days or thirty days. There are many hadiths in this meaning, from the hadith of Ibn 'Umar, Abu Hurayrah, Hudhayfah ibn al-Yaman, and others (may Allah be pleased with them) . It is known that the address of the Prophet (peace and blessings be upon him) is not specific to the people of Madinah, but it is an address to the Ummah as a whole in all their eras and cities until the Day of Resurrection. So whenever these two matters are available, it becomes possible for the Islamic states to agree on fasting all together. So we ask Allah to guide them to that, and to help them to implement the Islamic Shari'ah and reject what contradicts it.
There is no doubt that this is obligatory upon them; because of His saying, the Exalted: [An-Nisa: 65], and the verses that came with its meaning. There is also no doubt that in implementing it in all their affairs lies their well-being, their salvation, the unity of their ranks, their victory over their enemy, and their success in immediate and ultimate happiness. So we ask Allah to expand their chests for that and to help them with it, for He is the All-Hearing, the Near.