"A Bedouin came to the Prophet and said: 'I have seen the crescent.' So he said: 'Do you testify that none has the right to be worshipped but Allah? Do you testify that Muhammad is the Messenger of Allah?' He said: 'Yes.' So he said: 'O Bilal! Announce to the people that they should fast tomorrow.'"
Jami` at-Tirmidhi Book 8, Hadith 10
← Previous Hadith "The Messenger of Allah vowed to stay away from his wives for a month, so he stayed in a loft for twenty-nine days. They said: 'O Messenger of Allah, your vow was for a month,' so he said: 'The month is twenty-nine (days).'"

Jami` at-Tirmidhi Book 8, Hadith 9 Next Hadith → the Messenger of Allah said: "The two months of Eid will not both be deficient: Ramadn and Dhul-Hijjah."

Jami` at-Tirmidhi Book 8, Hadith 11