I love nativity scenes like the one at top (with details below it), Adoration of the Shepherds by 17th century painter Gerrit van Honthorst, in which the infant is not just bathed in light, but seems to be a source of light, as if incandescent with the Holy Spirit.
In this case the child appears to be the only source of light in the scene. Scenes illuminated by a single light source, usually a candle, were a recurring theme for Van Honthorst, as in his painting Childhood of Christ (above, second from bottom). In this he was similar in some ways to the French painter Georges de la Tour, though without the latter artist’s masterful sense of mystery and stillness.
Van Honthorst also used the theme of a nativity illuminated from the direction of the child in his painting of two years earlier, Adoration of the Child (above, bottom), but the effect is not the same.
Even though he has taken pains with the light source in Adoration of the Shepherds, you can tell his real interest as an artist was not with the mother and child, but in the faces of the shepherds, wonderfully defined and enlivened by the direct light and the sharp chiaroscuro it invites.
Gerrit van Honthorst on Web Gallery of Art, and here