The father waits for word of his son, and every runner on the horizon carries the weight of what the news might be. The watchman's straining attention is the posture of a man who cannot act and can only look, reaching toward an outcome already settled somewhere out of sight. To love someone is to become vulnerable to news about them you cannot control.
The king reads hope into the second runner, saying he too brings tidings, not yet knowing the tidings will break him. Dread lives in that gap. A man about to receive terrible news often steadies himself with the story he prefers. The hardest thing a father does is wait for what he already half suspects.