Allah, Exalted be His praise, says: "And pilgrimage to the House is a duty owed to Allah by people, for whoever is able to find a way to it; and whoever disbelieves, then indeed Allah is free of need of all the worlds." [Surah Al Imran: 97]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / Q8606