Many New Testament references draw out the power of light as a symbol for God’s radiant, loving truth as well as its occasional physical manifestation when God’s glory has a visible effect: “God is light” (1 John 1:5), “the glory of the Lord shone around them” (Luke 2:9), “[Jesus] is the light of the world” (John 8:12), “you are the light of the world” (Matt 5:14) and “walk as children of light” (Ephesians 5:8).
One of the ways light can be visualized is by closing your eyes and letting a bright, white star (or cross) of light emerge in the middle of your forehead, allowing it to become as still and three-dimensional as possible. If you have difficulty with such imaging, you can simply sense that the light is there, feeling its warmth. Let this light stand for the light of Christ through which you are lovingly known, a light which gently absorbs all the thoughts and feelings that rise. Be very still and present to God through this time in your intent. The more still your mind, the more still the light will be.
This practice can be extended now or at another time by letting the light slowly expand through your body as an opening, cleansing light, and then beyond your body, so that within and without there is an even light of God. Your breathing in and out is filled with this light.
Excerpted from Tilden Edwards, Living in the Presence: Spiritual Exercises to Open Our Lives to the Awareness of God