It seemed to Harry that the whole river was full of horsemen in an instant, and then he saw Stonewall Jackson himself, riding Little Sorrel into the stream.
Harry's horse stumbled once on the rocky bottom, but recovered his footing, and the boy urged him on toward the bank, bumping on either side against those who were as eager as he.

He was covered with water and foam, churned up by so many horses, but he did not notice it.

In a minute his horse put his forefeet upon the bank, pulled himself up, and then they were all formed up by Jackson himself for the pursuit.
"They run! They run already!" cried Sherburne.
They were not running, exactly, but Kenly, always alert and cool, had seen the passage of the ford by the Virginians, and unlimbering his guns, was retreating in good order, but swiftly, his rear covered by the New York cavalry.
Now Harry saw all the terrors of war.

It was not sufficient for Jackson to defeat the enemy.

He must follow and destroy him.