Hazrat Muslim narrates that a man came to Hazrat Ibn Abbas (may Allah be pleased with them) to ask about suhoor. One of Hazrat Ibn Abbas’s companions said to him,“Do not eat at the time when you are in doubt.”Hazrat Ibn Abbas (may Allah be pleased with them) said,“He has said nothing; eat as long as you are in doubt, until there is no doubt left.”

Hazrat Awn bin Abdullah narrates that two men came to Hazrat Abu Bakr while he was eating suhoor. One of them said that Fajr has begun. The other said that Fajr has not yet begun. Hazrat Abu Bakr said: Eat, there is a difference of opinion between the two.

It is narrated in the same way from Hazrat Abu Bakr through another chain of transmission.

Hazrat Mak'hool narrates that I saw Hazrat Ibn Umar (may Allah be pleased with them both) draw a bucket of water from the well of Zamzam. He asked two men, "Has Fajr dawned?" One of them said, "No," and the other said, "Yes." Upon this, Hazrat Ibn Umar (may Allah be pleased with them both) drank the water.

Ibrahim says: Eat until the light is in the form of width.

Hazrat Ikrimah says: Eat until there appears on the horizon a form like the tearing of a sheet.

Hazrat Ata narrates that Hazrat Ibn Abbas (may Allah be pleased with them) was eating sahur in the house of Hazrat Umm Hani during the month of Ramadan. One of his two servants said that Fajr had begun, while the other said that Fajr had not yet begun. He said, "Give me water to drink."

Hazrat Abu Ja'far says: "Eat until the dawn becomes apparent."

Hazrat Yazid bin Zaid said that a man asked Hasan, "If I am in doubt about the arrival of dawn, can I eat suhoor?" Hasan replied, "As long as you are in doubt, keep eating. By God! There is no concealment in the arrival of dawn."

Hazrat Umar says that when two people are in doubt about Fajr, then eat until both of them are certain.