A disciple suddenly discovered the richness of fecundity of emptiness -- the realization that everything is impermanent, unsatisfactory, and empty of self. In this mood of divine emptiness, he sat in joy under a tree, when suddenly flowers began to fall all around him.
And the angels whispered, "But I haven't uttered a word about emptiness."
"True," the angels replied. "You have not spoken of emptiness, we have not heard of emptiness. This is true emptiness." And the showers of blossoms continued to fall.
If the heart wanders or is distracted, bring it back to the point quite gently -- and even if you do nothing during the whole of your prayer but bring your heart back, though it went away every time you brought it back, your time would be very well employed.