The conception of equality is evident in Aristotle: he will not have equality between equal and different, it is necessary that both the parts are equal. The proper equal and different attempt of if establishing equality between, if will not have a factor of acquit positive that hangs for the side from the different one (becoming it, through this treatment of necessary, equal inaquality), will have injustice. They are implicit then, in the concept of aristotelian Justice, the principles of that ' ' it only has justice between iguais' ' that ' ' to establish the equality between equal and different indiscriminately is injusto' '. Justice is, therefore linked to the proportionality concept, flowing out itself that just it is the proportional one. The friendship (filia), as already said, is most important of the external goods, and also it is a virtue or it involves a virtue, is a sine qua non condition so that the happiness can be reached by the man, is an additional attribute to the elements that already had been mentioned. The relation between friends demands proportionality as justice, the love between friends is proportional, when loving a friend loves its proper one well and this reciprocal is considered, in fact, it has a relation of mutual affection, wants the good and to make the good therefore, in this direction, is a solidary idea for both the parts in the context of the friendship relation. In Ethics the Nicmaco, the most illustrious Greek philosopher, assevera ' ' Ademais, the friendship seems to be the bond that joins the State; the legislators more seem to watch over for it of what for justice, a time that to promote the concord, that if it figures related to the friendship, constitutes the main objective of them, while banishing of the discord, that is enmity, it is its bigger concern. .