The Hidden Words, written in Baghdad around 1858, consists of seventy-one short passages in Arabic and eighty-two in Persian, each opening with an address — O Son of Spirit, O Son of Man, O Son of Being, O Son of Utterance. Bahá'u'lláh describes it as the inner essence of what was revealed to the prophets of old, clothed in brevity. The passages are ethical and mystical rather than legal, and they are short enough to memorise, which is what Bahá'ís do with them: they are quoted in ordinary conversation, printed on cards, and used to open meetings. It is also the text most often given to non-Bahá'ís, being brief, non-technical and free of institutional content. Its literary register in English is Shoghi Effendi's, and the best-known lines — O Son of Spirit, my first counsel is this: possess a pure, kindly and radiant heart; and, O Son of Being, love me that I may love thee — are the ones an outsider is most likely to have encountered.