St Bonaventure describes the three stages, corresponding to the three gifts of the wise to mankind, in The Triple Way. “First, the steps of cleansing. The first level of spiritual life, purification, is divided in this manner: You must blush because of your crimes; tremble in the face of judgment; weep for the damage done; beg for remedy; fight the enticements of the enemy (the devil); desire martyrdom on account of the reward, and come close to Christ seeking shelter in him.”
“The steps pertaining to illumination [the second stage] are divided in this manner: Consider who it is that is suffering [Christ Crucified] and surrender with faith. How good is the One who is suffering and be filled with deep compassion. How great is the One who is suffering and be carried away with admiration. Why he is suffering and be filled with trust and gratitude. How he is suffering and be led to conform to him. How much he is suffering and embrace him with ardour. What are the consequences of his suffering and contemplate him with deep insight.”
“The steps of the unitive way, the third level of spiritual life, are divided in this manner: Watchfulness must arouse you since the spouse is at hand. [The spouse of our soul is Jesus Christ.] Trust must strengthen you since he is faithful. Desire must inflame you since he is sweet. Rapture must uplift you since he is lofty. Delight in him must bring you peace since he is beautiful. Joy must inebriate you since his love is full. Close proximity must weld you to him since his love is strong. Thus, in the intimacy of our loving soul let us always say to the Lord, ‘It is You I seek, in You I hope, for You I long, to You I rise, You I receive, in You I exalt, and to You I finally cling.’” (Translation borrowed from Spiritual Substance.)
Another way of looking at the three gifts is as representing the gifts man gives to God – the essence of liturgy through the ages. The heart of the liturgy is the sacrifice itself (myrrh). The whole is animated by prayer, represented by the frankincense that rises to heaven. Finally we offer the glories of art (gold), representing heaven, to which the liturgy admits us.