Majma al-Zawaid — Hadith 12199

Alqamah bin Abdullah al-Muzani narrates: A man told me this; he said: I was present in a gathering in which Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) was also present; this was in Madinah. He said to a man among those present: O so-and-so! How did you hear the Prophet (peace and blessings be upon him) describe Islam? That man said: I heard the Prophet (peace and blessings be upon him) say: "Indeed, Islam began as a jadha' (that is, a young camel), then it became a thani (that is, one entering its third year), then it became a raba'i (that is, a camel entering its fourth year), then it became a sadis (that is, a camel entering its eighth year), then it became a bazil (that is, one that has completed eight years and entered its ninth)." Then Sayyiduna Umar (may Allah be pleased with him) said: After becoming "bazil", nothing remains but decline.
Ahmad and Abu Ya'la recorded it; its chain contains a narrator who is not named, and the rest of its narrators are thiqat (trustworthy).