The work announces its own purpose in a short preamble: this is that which hath descended from the realm of glory, the inner essence of what the tongues of the prophets have uttered aforetime, taken and clothed in brevity as a token of grace, that all may stand faithful to the covenant of God. What follows are not laws or arguments but addresses, God speaking directly to the soul under names that map the soul's conditions: O Son of Spirit for counsels of the heart's nobility, O Son of Man for tenderness and testing, O Son of Dust for warnings against attachment, O My Servant for the summons to action. The first Arabic word sets the tone of the whole, counselling the possession of a pure, kindly and radiant heart as an ancient and imperishable sovereignty. Recurring themes bind the two parts: love as the reason for creation, justice named the best beloved of all things in God's sight, death made a messenger of joy, wealth and poverty weighed by detachment, the nearness of God to the one who remembers him.
The Persian part grows more imagistic, with nightingales, gardens and the friend, drawing on the idiom of Persian mystical poetry while redirecting it. Bahai practice has answered the book's design: passages are memorised, set to music, and read in devotional gatherings across the worldwide community, and Shoghi Effendi's English translation fixed phrases now common in Bahai speech.