The Adornment of the Spiritual Marriage, by Jan van Ruysbroeck, , at sacred-texts.com
The first coming of Christ in the exercise of desire is, as we have said, an inward and sensible thrust of the Holy Ghost, urging and driving us towards all virtues. This coming may be likened to the splendour and the power of the sun, which, from the moment when it rises, enlightens and brightens and warms the whole world. 43 So likewise Christ, the eternal Sun, beams and shines, dwelling above the summit of the spirit; and enlightens and enkindles the lowest part of man, namely, the fleshly heart and the sensible powers. And this happens in a moment of time, shorter than the twinkling of an eye; for God's work is swift. But that man in whom this should take place must be inwardly seeing, with the eyes of the understanding.
In the higher lands, in the middle region of the world, the sun shines upon the mountains, bringing an early summer there, with good fruits and strong wine, and filling that land with joy. The same sun gives its splendour to the lower lands, at the utmost part of the earth. There the country is colder, and the power of the heat less; nevertheless, there too it produces many good fruits, though little wine. The men who dwell in the lower parts of themselves, in their outward senses, yet with a good intention, in moral virtues, in outward work, and in the grace of God: they too produce the good fruits of virtue, in great numbers and in many ways; but of the wine of inward joy and ghostly consolation they taste little.
Now the man who wishes to feel within himself the glow of the Eternal Sun, which is Christ Himself, he should be seeing, and should dwell on the mountains in the higher lands, by a gathering together of all his powers, and lifting up his heart towards God, free and careless of joy and grief, and of all created things. There Christ, the Sun of righteousness, shines upon the free and uplifted heart: and these are the mountains that I mean.
Christ, the glorious Sun, the Divine Brightness, by His inward coming and by the power of His Spirit, enlightens and brightens and enkindles the free heart and all the powers of the soul. And this is the first work of the inward coming in the exercise of desire. Like as the power and the nature of fire enkindles everything which is offered to the flames, so Christ, by the fiery ardour of His inward coming, enkindles every ready, free and uplifted heart; and in this coming He says: Go ye out by exercises according to the way of this coming.