Abu Nadra reported,

Ibn Abbas used to permit combining Hajj and Umrah, while Ibn Zubayr forbade it. The narrator said, "So I mentioned this to Jabir bin Abdullah."Jabir replied, "This matter passed through my own hands. We performed Umrah together with the Messenger of Allah ﷺ. Then, when Umar came to power, he said, 'Allah used to make lawful for His Messenger whatever He willed in whatever manner He willed, and the Quran has now come down in its proper places. So "complete the Hajj and the Umrah for Allah" [Baqarah 2:196], as Allah has commanded you. And make your marriages to these women permanent, for no man will be brought to me who has married a woman for a fixed term without my stoning him with stones.'"And in the hadith Umar also said, "Keep your Hajj separate from your Umrah, for that is more complete for your Hajj and more complete for your Umrah."

Muslim 2948

Sahih

و حدثنيه زهير بن حرب حدثنا عفان حدثنا همام حدثنا قتادة بهذا الإسناد وقال في الحديث فافصلوا حجكم من عمرتكم فإنه أتم لحجكم وأتم لعمرتكم

مسلم 2948صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Hajj
Chapter
Tamattu in Hajj and Umrah
Numbering
Darussalam 2948
Muslim 2948