All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The sighting of the month of Ramadan is confirmed by the sighting of the crescent or by the completion of the month of Sha'ban (the month preceding Ramadan) thirty days. The evidence for this is the Hadeeth reported by Al-Bukhari and Muslim “When you see the new moon, observe fast, and when you see it (again) then break the fast, and if the sky is cloudy for you, then complete thirty days for the month of Sha'baan.”
So the messenger of Allah made the fasting and the breaking of the fast both according to the sighting of the crescent.
This was the custom among the companions and the early Muslims the predecessors and their followers who lived in the first three centuries of Islam which were described by the Messenger of Allah as the best centuries.
The brothers in Saudi Arabia are the most keen to apply this and the following is a statement in the Fataawa of the Permanent Council of Fatwa in Saudi Arabia:
“Saudi Arabia adheres to the tradition of the Prophet and the rightly-guided predecessors as far as the confirmation of the sighting of the crescent of Ramadan, ‘Eed al-Fitr and Eed al-Adh-ha, times of Hajj and the like are concerned. In fact, the good (all the good) is in following the rightly guided predecessors and the evil (all the evil) is in innovations (in religion).”
Allah knows best.