Sa'id bin al-Musayyib (may Allah have mercy on him) said: A man from among the Companions (may Allah be pleased with them) came to Umar bin al-Khattab (may Allah be pleased with him) and testified that he had heard the Messenger of Allah (peace and blessings be upon him), in the illness in which he passed away, forbidding Umrah before Hajj.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8868