To elaborate some on mysticism in respects to Christian art, Jesus Christ wearing the crown or emanating a halo is symbolic of Enlightenment, while pointing at his heart is symbolic of Understanding, the flame that is often associated with the sacred heart is symbolic of Life. The shape surrounds Jesus Christ in this picture is called Vesica Piscis and is the shape that occurs when two circles intersect each other's center. Therefore Vesica Piscis is symbolic of the making of the two into One.
22. Jesus saw some babies nursing. He said to his disciples, "These nursing babies are like those who enter the kingdom."
They said to him, "Then shall we enter the kingdom as babies?"
Jesus said to them, "When you make the two into one, and when you make the inner like the outer and the outer like the inner, and the upper like the lower, and when you make male and female into a single one, so that the male will not be male nor the female be female, when you make eyes in place of an eye, a hand in place of a hand, a foot in place of a foot, an image in place of an image, then you will enter [the kingdom]." -Gospel of Thomas