Then Solomon said, “The LORD intends to dwell in the dark cloud;
I have truly built you a princely house, a dwelling where you may abide forever.”
Cloud and light. These two images occur together in the manifestations of the Holy Spirit. In the theophanies of the Old Testament, the cloud, now obscure, now luminous, reveals the living and saving God, while veiling the transcendence of his glory - with Moses on Mount Sinai, at the tent of meeting, and during the wandering in the desert, and with Solomon at the dedication of the Temple. In the Holy Spirit, Christ fulfills these figures. The Spirit comes upon the Virgin Mary and "overshadows" her, so that she might conceive and give birth to Jesus. On the mountain of Transfiguration, the Spirit in the "cloud came and overshadowed" Jesus, Moses and Elijah, Peter, James and John, and "a voice came out of the cloud, saying, 'This is my Son, my Chosen; listen to him!'" Finally, the cloud took Jesus out of the sight of the disciples on the day of his ascension and will reveal him as Son of man in glory on the day of his final coming.
-- CCC 697