How we cite our quotes: (Book.Chapter.Bekker #s); all Bekker line numbers are approximate, since they are keyed to the original Greek.
Quote #7
Further, there is also the need of the passage of time and the habits formed by living together; for as the adage has it, it is not possible for people to know each other until they have eaten together the proverbial salt, nor is it possible, before this occurs, for them to accept each other and to be friends until each appears to each as lovable and is trusted. (8.3.1156b26-28)
This seems like a lot of work to say that someone is our friend. But Aristotle wants to make sure that we don't jump headfirst into an inferior friendship that'll end in a lot of heartache.
First requirement: friends have to spend a lot of time together. In doing so, two things happen: we become like each other (similar habits) and we learn to trust. It's also important that each person finds something stable in the other person to admire. Otherwise, we might wind up with a friendship of convenience rather than the real thing.
Quote #8
Friendship appears in each of the regimes to the extent that what is just does as well. In a king in relation to those over whom he is king, friendship consists in superiority in granting benefactions, for he benefits those over whom he is king—if in fact, being good, he cares for them so that they fare well, just as does a shepherd for his sheep. (8.11.1161a10-14)
Because friendship is intimately connected to justice, Aristotle has no problem making the leap into political relationships to see how they form under different types of rule. The king is superior of course—like the father to a son—and can't extend friendship of equality to his subjects. But in order to keep monarchy in line (i.e. away from tyranny) there has to exist some of the same affection that we have in friendships to keep the balance of power on the right side of justice.
Quote #9
The friendship of a husband for a wife is the same as that in aristocracy, for it accords with virtue, and to the better person goes more of the good and to each what is suited to each. So also in the case of what is just. The friendship of brothers is like that of comrades...also resembling this friendship is the friendship pertaining to timocracy, for the citizens wish to be equals and equitable. (8.11.1161a23-27)
Aristotle continues to map the concept of intimate friendships onto political life in order to see how these relationships work on the macrocosmic levels. What we see happening in households can be seen in society at large, as is the case in the friendship between husband and wife and brothers.
There's no equality in marital friendship (hey, it's ancient Greece), but there is a kind of kindred nobility there, and a sense that each partner merits their own things. Brothers are the closest to total equality, like a timocracy—a polity governed by those who pay property taxes.