[73] Therefore, as a man who is being carried away by a torrent shudders at the nearest waves by which he is being hurried away, and still more at those coming upon him from above, since the one is continually and incessantly propelling him forward with violence, but the other being raised above him threatens to overwhelm him utterly, so in the same manner those evils which are present are grievous, but those which proceed from fear of the future are more grievous still; for fear continually supplies sorrowful feelings as from an everlasting spring.