The Kitáb-i-Aqdas
54.The Lord hath ordained that those of you who are able shall make pilgrimage to the sacred House   ¶32
Two sacred Houses are covered by this ordinance, the House of the Báb in Shíráz and the House of Bahá’u’lláh in Baghdád. Bahá’u’lláh has specified that pilgrimage to either of these two Houses fulfils the requirement of this passage (Q&A 25, 29). In two separate Tablets, known as Súríy-i-Hajj (Q&A 10), Bahá’u’lláh has prescribed specific rites for each of these pilgrimages. In this sense, the performance of a pilgrimage is more than simply visiting these two Houses.
After the passing of Bahá’u’lláh, ‘Abdu’l-Bahá designated the Shrine of Bahá’u’lláh at Bahjí as a place of pilgrimage. In a Tablet, He indicates that the “Most Holy Shrine, the Blessed House in Baghdád and the venerated House of the Báb in Shíráz” are “consecrated to pilgrimage,” and that it is “obligatory” to visit these places “if one can afford it and is able to do so, and if no obstacle stands in one’s way.”1 No rites have been prescribed for pilgrimage to the Most Holy Shrine.
1 Synopsis and Codification of the Kitáb-i-Aqdas, page 61, no. 26