Suraqah bin Malik bin Ju'shum (may Allah be pleased with him) said: I saw the Messenger of Allah (peace and blessings be upon him) standing in the valley delivering a sermon, and he (peace and blessings be upon him) was saying: "Umrah has entered into Hajj until the Day of Resurrection."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8772