Buch der heiligen Dreifaltigkeit, c. 1430, Germanisches Nationalmuseum
"Truly, without falsehood, a certain truth: that which is below is like that which is above, and this is the whole miracle. The stone is not a stone: brother and sister, body and spirit, lime and water, male and female, king and queen. And Hermes says that our stone consists in two natures. It is of the nature of air, and in twelve months and in one day it is transformed; its day is the burning of fire in the morning, and afterward it is the sun and the moon, and the purifying wind by its own operation, within and without, air and earth. The philosophers have explained it in various ways. It is nothing other than a beautiful discovery, the operation and maturation of the seven. Each part acts according to its nature, and through them all metals are mixed. The seven complete the work, and gradually it is elevated; the seven are mingled and exalted, becoming white and red, without deceit. Thanks be to God. This is the true magnet, the unity of the materials."
On the left side is written: horn of the dragon, water, fire, the color of fire. On the right side is written: air, this is the color of air, clouds, this color is clear air, clear air. Beneath the left plant is written: earth, the color of earth. Beneath the right plant is written: burned earth. Between the two dragons is written: the concord of the brothers. Beneath the dragon is written: the dragon itself is the serpent in which the great secret lies hidden. Beneath the central figure is written: here is the double man, the united matter.
"Here begins the teaching of how the soul, strengthened by divine knowledge, rises from earthly limitation and receives the light of heavenly wisdom. All creatures that are formed according to God’s will bear His likeness in their innermost being. Thus the soul, when purified, must become receptive to the grace that flows from the Holy Spirit, who enlightens all minds and strengthens all virtues. And therefore the wise say that the human heart is the dwelling of divine truth, and whoever keeps it pure shall behold the wonders of God in this life and the next. For every joy and every sorrow leads the faithful soul closer to the eternal good, just as the sun draws every creature towards its warmth. So it is written that the righteous must prepare themselves through discipline, humility, and the inner work of contemplation, for in these virtues the soul grows strong and becomes a vessel of divine knowledge. And when the heart is thus prepared, it shall receive the heavenly illumination which surpasses all reason, and shall rest in the peace of God, from which springs the perfect love that knows no end. Here are shown the essential elements of the inner transformation: First, the cleansing of the soul; Second, the uplifting of the heart; Third, the enlightenment of the mind; Fourth, the uniting with divine truth; Fifth, the perfecting of the will, that the whole human being may be renewed in God’s likeness. And whoever attains this shall know the eternal wisdom that flows from the Holy Spirit and is the root of all virtues, and shall not be moved by any earthly temptation."