Zayd bin Jubayr said: I was with Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) when he was asked about this, that is, someone on whom Hajj is obligatory and who vows a Hajj. He said: This is the obligatory Hajj of Islam; let him seek to fulfil his vow.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8691