The Discourses of Epictetus, tr. by P.E Matheson, , at sacred-texts.com
If a man could only take to heart this judgement, as he ought, that we are all, before anything else, children of God and that God is the Father of gods and men, I think that he will never harbour a mean or ignoble thought about himself. Why, if Caesar adopts you, your arrogance will be past all bearing; but if you realize that you are a son of Zeus, will you feel no elation? We ought to be proud, but we are not; as there are these two elements mingled in our birth, the body which we share with the animals, and the reason and mind which we share with the gods, men in general decline upon that wretched and dead kinship with the beasts, and but few claim that which is divine and blessed.
And so, since every one, whoever he be, must needs deal with each person or thing according to the opinion that he holds about them, those few who think that they have been born to be faithful, born to be honourable, born to deal with their impressions without error, have no mean or ignoble thought about themselves. But the thoughts of most men are just the opposite to this. 'What am I? A miserable creature of a man'; and 'my wretched rags of flesh'. Wretched indeed, but you have too something better than your 'rags of flesh'. Why then do you discard the better and cling to your rags?
By reason of this lower kinship some of us fall away and become like wolves, faithless and treacherous and mischievous, others like lions, savage and brutal and untameable, but the greater part of us become foxes and the most god-forsaken creatures in the animal world. For a foul-mouthed and wicked man is no better than a fox or the meanest and most miserable of creatures. Look to it then and beware lest you turn out to be one of these god-forsaken creatures.