Sayyiduna Ibn Abi Awfa (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) combined Hajj and Umrah because he knew that he would not perform Hajj after that.
Imam al-Bazzar recorded it, and Imam al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat. Its chain contains a narrator, Yazid bin Ata', whom Imam Ahmad and others declared thiqah (trustworthy), and there is some criticism of him.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الحج / 5446