It is narrated from Ibn Umar (may Allah be pleased with them both) that Umar (may Allah be pleased with him) said: "None among the pilgrims should return until his last act is performed at the House of Allah. Indeed, the final act of Hajj is the (farewell) Tawaf of the House of Allah."
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 1030
Hadith Takhrijإسناده صحيح أخرجه البيهقي: 5 / 162 - وفي معرفة السنن والآثار له (3097) وابن أبي شيبة (13596)۔