Fundamentally our true heart, our true nature, is pure and infinite, like the moon clear in the blue sky. At some distant time past our knowing, it was tainted by passion and became the impure heart, something not our real selves but which came afterwards. But this which came afterwards becomes predominant and sets at naught the true heart, just as the concubine sets at naught the true wife. How often one has read in the papers that the steward of some large estate, or the manager of a great firm perhaps, has set at naught his true masters and using the money for himself has brought ruin all round. Just in this way we entrust ourselves to the operations of the deluded and passion-ridden heart, so that the true master, the Buddha heart, cannot even show its face. The thoughts of the impure heart are topsy-turvy, for it sees reality as upside down.
– Takashina Rosen. A Tongue-Tip Taste of Zen.