In Book Two of the Masnavi, Rumi employs the metaphor of a skilled gardener to illustrate the spiritual insight of the Perfect Man (such as the King or the Sheikh). Just as a gardener can differentiate between a tree that will yield bitter fruit and one that will bear sweet fruit long before they actually fruit, the spiritually illuminated leader sees the true inner nature of individuals. This metaphor explains the King's apparent favoritism toward his special slave over his other emirs; the King uses the 'light of God' to foresee the emirs' inner bitterness and the slave's hidden spiritual wealth, treating them accordingly.