It is narrated from Zaid bin Jubair that he said: "I was with Abdullah bin Umar (may Allah be pleased with them) when he was asked about this, so he said: This is the Hajj of Islam; he should fulfill his vow." That is, the one upon whom Hajj is obligatory and he has made a vow to perform Hajj.
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 922
Hadith Takhrijإسنادہ حسن أخرجہ البیہقی: 4 / 339 - وفی معرفۃ السنن والآثار لہ (2684) ۔ وابن ابی شیبہ (12739)۔