Nafi' bin Jubayr (may Allah have mercy on him) narrates from his father, Sayyiduna Jubayr bin Mut'im (may Allah be pleased with him), who said: I saw the Prophet (peace and blessings be upon him) trimming his hair on al-Marwah with an arrowhead (mishqas), and he (peace and blessings be upon him) said: "Umrah has entered into Hajj until the Day of Resurrection."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1569