For both the Diamonds were just grandly obedient.

And Diamond soon found that, as he was obedient to his father, so the horse was obedient to him.

For he had not ridden far before he found courage to reach forward and catch hold of the bridle, and when his father, whose hand was upon it, felt the boy pull it towards him, he looked up and smiled, and, well pleased, let go his hold, and left Diamond to guide Diamond; and the boy soon found that he could do so perfectly.

It was a grand thing to be able to guide a great beast like that.

And another discovery he made was that, in order to guide the horse, he had in a measure to obey the horse first.