The Messenger of Allah ﷺ said, "The believer feels protective jealousy, the believer feels protective jealousy, the believer feels protective jealousy, and Allah's jealousy is greater still."
حدثنا ابن أبي عدي عن شعبة عن العلاء عن أبيه
قال رسول الله ﷺ المؤمن يغار المؤمن يغار المؤمن يغار والله أشد غيرا
Its isnad is sahih. Muslim narrated it, 2/327, via Muhammad bin Jafar from Shubah, with this isnad, in a similar wording, and he narrated it before that via Darawardi from Ala. See what has already passed in Musnad Ibn Masud, 4153.As for his statement "the believer feels jealousy," it is mentioned once in copy K, and mentioned twice in copy M, and both carry the mark of soundness. It is mentioned three times in copy H, but I found nothing to support the third occurrence, so I removed it. In Sahih Muslim it reads, "the believer feels jealousy, the believer feels jealousy." However, "the believer feels jealousy" (the second occurrence) was not mentioned in the Istanbul edition (p. 101), and I have restored it in agreement with the two sound manuscripts I possess, the manuscript of Shatti and the manuscript of Shaykh Abid Sindi, on both of which the correction mark was written.As for his statement "wallahu ashaddu ghayran" (Allah is more jealous), it has a fatha on the dotted ghayn and a sakin ya, with no ha at the end, meaning jealousy (ghayrah). In Lisan al-Arab, 6/347, Ibn Sidah said, "A man feels jealous (yaghar) over his wife, and a wife over her husband, taghaar ghayrah, wa ghiyaran, wa ghuwaran."