The Duke believed that his son-in-law, who came far away from the neighboring kingdom, would not bring proper attire for a banquet, as he came not to attend a grand event but to visit and take his wife back to the place where he lived.
The Duke was actually worried when he received the royal invitation letter. The King seemed to have haste to celebrate the birthday of the Crown Prince for the General to attend, but he did not think about how the General would adorn himself if there were only very limited time to prepare the suit.
If the General's body size were not taller and bigger than his, he would not have worried, as he could just give him one of his suits to wear. Even Phillip, his son, was not as tall and big as the General.