Here’s the text of Isocrates’ famous “Hymn to Logos” in which he praises the community-building function of rhetoric.
It’s from the opening of Isocrates’ speech, “Nicocles” (B.C. 372-365).
Below I provide a side-by-side comparison of English translations from 1980 (left) and 1735 (right).
1980 translation by George Norlin
 But the fact is that since they have not taken the trouble to make distinctions after this manner in each instance, they are ill-disposed to all eloquence; and they have gone so far astray as not to perceive that they are hostile to that power which of all the faculties that belong to the nature of man is the source of most of our blessings.
For in the other powers which we possess we are in no respect superior to other living creatures; nay, we are inferior to many in swiftness and in strength and in other resources;
 but, because there has been implanted in us the power to persuade each other and to make clear to each other whatever we desire, not only have we escaped the life of wild beasts, but we have come together and founded cities and made laws and invented arts; and, generally speaking, there is no institution devised by man which the power of speech has not helped us to establish.
1735, translated by James Brown
[p. 27] But such are to be blam’d as make an ill Use of good Faculties, and endeavour to employ those Means to the Prejudice of their Fellow-Citizens, by which they might benefit them. Now some People are without Distinction averse to all kinds of Eloquence, and are so deeply in an Error, that they do not perceive themselves to be Enemies to the Thing, which is above all others the Cause of the greatest Advantages to human Nature.
For in other Things we do not at all excel the Beasts: We are much inferior to them in Swiftness and Strength, and other Faculties.
But by our having an innate Power of persuading, and of revealing our Thoughts to one another, we have not only left off the Savage kind of Life, but upon joining together, we have peopled Cities, founded Laws and invented Arts; and it is to the Art of Speaking chiefly that all our Inventions are owing:
| For this it is which has laid down laws concerning things just and unjust, and things base and honorable; and if it were not for these ordinances we should not be able to live with one another.
It is by this also that we confute the bad and extol the good.Through this we educate the ignorant and appraise the wise; for the power to speak well is taken as the surest index of a sound understanding, and discourse which is true and lawful and just is the outward image of a good and faithful soul.
 With this faculty we both contend against others on matters which are open to dispute and seek light for ourselves on things which are unknown; for the same arguments which we use in persuading others when we speak in public, we employ also when we deliberate in our own thoughts; and, while we call eloquent those who are able to speak before a crowd, we regard as sage those who most skilfully debate their problems in their own minds.
it is this that has given the Definition of Justice and Injustice, of base and good Actions; without which Determinations we could not have liv’d together.It is from hence we draw our Convictions against bad Men and our Encomiums on the Good.[p. 28]
It is by this we instruct the Simple and prove the Prudent. For to speak as is becoming, is universally allowed to be the greatest Token of true Judgment, as Truth and Equity are the Image of an honest and faithful Mind;and these are the means by which we struggle with Doubts and search into Things unknown.
The same Arguments which we use to persuade with, serve us in our Thoughts about our own Affairs. And we call those Eloquent, who are able to speak well to the Multitude; and we esteem those prudent who can best argue with themselves concerning Things.
| And, if there is need to speak in brief summary of this power, we shall find that none of the things which are done with intelligence take place without the help of speech, but that in all our actions as well as in all our thoughts speech is our guide, and is most employed by those who have the most wisdom.Therefore, those who dare to speak with disrespect of educators and teachers of philosophy deserve our opprobrium no less than those who profane the sanctuaries of the gods.||But to be brief, upon this Endowment, we shall find that nothing can be performed prudently without Words, which are the Guide of all Works and Thoughts; and they are the wisest that make most use of them.So that they who dare speak impiously of Instructors and Philosophers are no less to be detested than those who violate the Temples of the Gods.|
Source 1: Isocrates. Isocrates with an English Translation in three volumes, by George Norlin, Ph.D., LL.D. Cambridge, MA, Harvard University Press; London, William Heinemann Ltd. 1980. Retrieved from http://data.perseus.org/citations/urn:cts:greekLit:tlg0010.tlg014.perseus-eng1:5
Source 2: Isocrates. (1735). Nicocles [To his subjects the Cyprians, concerning their Duty]. In J. Brown (Trans.), The duty of a king and his people: being two orations of Isocrates; the one containing The duty of a king; the other containing The duty of subjects (pp. 26–43). London: printed for J. Roberts.