Keeping Purity of Heart in View

It is like a man who tries to strike some great prize of virtue set up on high and marked out by a very small target. He aims his dart with the keenest eye, knowing that great rewards of glory and prizes depend on his hitting it. He turns his gaze away from everything else and must direct it there, where he sees the reward and the prize are placed. For he would surely lose the prize for his skill and the reward for his strength if the keenness of his gaze were turned aside ever so little. [a]