Majma al-Zawaid 11038 — The saying of Allah the Exalted

Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: The Arabs used to declare one month lawful in one year and two months lawful in another year, so they would reach the correct time of Hajj only once every twenty-six years. This is the postponement (nasi') that Allah Almighty mentioned in His Book. When the year came in which Sayyiduna Abu Bakr (may Allah be pleased with him) led the people in Hajj, that year coincided with the true Hajj, so Allah Almighty named it the Greater Hajj. Then in the following year the Prophet (peace and blessings be upon him) performed Hajj, and the people began to keep correct count of the new moons. The Prophet (peace and blessings be upon him) said: "Indeed, time has come round to the way it was on the day Allah Almighty created the heavens and the earth."
Imam al-Tabarani recorded it in al-Mu'jam al-Awsat, and its narrators are thiqat (trustworthy).