A little later in the dialogue, the Athenian proposes that the real reason for which Cretan law should be praised, and the proper purpose of the law, is the way it regulates all the aspects of society in order to create human happiness.
"The Cretan laws are with reason famous among the Hellenes; for they fulfil the object of laws, which is to make those who use them happy; and they confer every sort of good."
Note how total this is: "Some... ordinances will relate to contracts of marriage which they make one with another, and then to the procreation and education of children, both male and female; the duty of the lawgiver will be to take charge of his citizens, in youth and age, and at every time of life, and to give them punishments and rewards."
This is a fundamental difference in how we see society from how Plato sees it, although it is in line with how progressives see it. The government should have all power, and perform all functions, necessary to bring about maximized human happiness. Laws should require people to behave in the right ways.
We then get a very strange ranking of the goods of life. They are of two kinds, human and divine. The human goods are lesser, and are attained by striving first for the greater divine goods. These goods, which are virtues, have a rank as well.
"Of the lesser goods the first is health, the second beauty, the third strength, including swiftness in running and bodily agility generally, and the fourth is wealth... [W]isdom is chief and leader of the divine dass of goods, and next follows temperance; and from the union of these two with courage springs justice, and fourth in the scale of virtue is courage. All these naturally take precedence of the other goods, and this is the order in which the legislator must place them, and after them he will enjoin the rest of his ordinances on the citizens with a view to these...."
The ranking of the virtues is odd, I say, because it has no clear priority. Wisdom is chief, but also a precondition for Justice. Thus, it makes sense if Justice is considered of a lower rank, since Wisdom must be pursued first in order to create the conditions for Justice to be possible. Yet notice that courage, also a precondition for Justice, is considered of the fourth rank rather than the third.
It's not clear to me what Plato is thinking of here. He plainly wants to say something like "It's more important to be wise than courageous," but that itself is out of order with what has usually been Plato's position as expressed through Socrates, i.e., that virtue is a kind of knowledge or wisdom. To be courageous is to be wise, in a way. Here wisdom is severable from courage, and even partly from justice.
The Athenian here is not Socrates, and here at least is a proof of it. He is approaching courage as something different; and, as Aristotle will do in his own ethics, Plato is going to at once demote it to a lesser rank among the virtues yet also use it as the first and paradigmatic example of what a virtue is.
"I think that we must begin again as before, and first consider the habit of courage; and then we will go on and discuss another and then another form of virtue, if you please."
Also, having disposed of 'victory in war' as the key end of the state, the rest of the first book returns to it as a primary concern. Education is said to be good in that it produces victory, for example; courage is only properly courage and not a vice like rashness if it is ordered to victory.
All in all, a strange opening to a significant work. Note also the distinction between foreign and civil wars, and the perfection of virtue that is required only in the second -- which is nevertheless said to be a worse form of war, though it perfects virtues in its victors, which is supposed to be the true purpose of the state.
