In his speech On Imperial Rule (or On Monarchy), Synesius of Cyrene offers some advise to the emperor Arcadius (r.395-408). More information about this speech, together with a brief summary, can be found here.
Throughout this speech, the word "Scythians" refers to the Tervingian Germans (who would later be known as Visigoths), whereas "king" refers to emperor.
The text is offered here in the translation by A. Fitzgerald. The four-digit numbers are page numbers of the Migne edition.
On Imperial Rule 10
  Now that I have arrived at this point, if I bring down what is the common ground of the discussion into the matter of the present discourse, my shot will not fall, I fancy, off the mark.
Who knows if I shall arouse your soul with the aid of the god
when I speak? For the counsel of a true man is excellent.note[Homer, Iliad 15.403.]
 I assert, in fact, that nothing has done the Romans more harm in past days than the protection and attention given to the sovereign's person, of which they make a secret as though they were priests, and their public exposure in barbaric fashion of the things that pertain to you. Truth and fantasy are not wont to consort together. But do not be incensed, for the fault is not yours, it is the fault rather of those who first created this mischief and transmitted to Time's heritage an evil now zealously maintained.
 Accordingly, this majesty and the fear of being brought to the level of man by becoming an accustomed sight, causes you to be cloistered and besieged by your very self, seeing very little,  hearing very little of those things by which the wisdom of action is accumulated. You rejoice only in the pleasures of the body, and the most material of these, even as many as touch and taste offer you; and so you live the life of a polyp of the sea.note[Aristotle, Nicomachean Ethics 1118a, 1148a, 1150a; Plato, Philebus 21c.]
 As long as you deem man unworthy of you, you will not attain man's perfection. Those with whom you consort in your round of life, and in other ways, and to whom access to the palace is safer from fear than to generals and captains of divisions, those on whom you bestow your royal approval are rather men with small heads and petty minds whom nature by some error stamps amiss, even as dishonest bankers falsify coins.note[Dio Chrysostom, Discourse 3 18.] A dullard becomes a gift for a king, and the duller he be the greater the gift. These men at once ready to laugh and weep without measure, playing the buffoon with gestures, noises, and every means in their power, these men I say aid you to destroy your leisure, and encourage by a greater evil that foggy blindness of mind which you have contracted from living a life not in accord with nature. The half-baked thoughts and conversation of these men suit your ears better than a philosophical sentiment, clearly and tersely expressed. And however much pleasure you have derived from this amazing inactivity, distrusting the thinking part of your people, and giving yourself solemn airs before them, while bringing the brainless elements close to you, and stripping before them: you should clearly understand that each thing increases by arts the same as those by which it is welded together.
 Review in your mind any kingdom established anywhere you please in the world, whether that of the Parthians, or the Macedonians, or the ancient Medes, or that in which we live now: men of the people who were soldiers as well, for the most part encamping together and sleeping on the ground in their formations, neither sparing themselves labors nor giving way excessively to pleasures, have carried each dominion far and wide. Men like these who acquire such great things though their devotion, and have become inflamed with zeal, would scarcely maintain their ranks without prudence. For good fortune seems to be a burden heavier than lead; at all events it overturns the man who has shouldered it, unless he happens to be all-powerful.