All his insulting epithets are shown by facts to be false
Basil is called 'hasty' and 'insolent,' and in both characters 'a liar' by this man who 'would in patience and meekness educate those of a contrary opinion to himself;' for such are the airs he gives himself when he speaks of him, while he omits no hyperbole of bitter language, when he has a sufficient opening to produce it. On what grounds, then, does he charge him with this hastiness and insolence? Because 'he called me a Galatian, though I am a Cappadocian;' then it was because he called a man who lived on the boundary in an obscure corner like Corniaspine a Galatian instead of an Oltiserian; supposing, that is, that it is proved that he said this.
I have not found it in my copies; but grant it. For this he is to be called 'hasty,' 'insolent,' all that is bad. But the wise know well that the minute charges of a faultfinder furnish a strong argument for the righteousness of the accused; else, when eager to accuse, he would not have spared great faults and employed his malice on little ones. On these last he is certainly great, heightening the enormity of the offense, and making solemn reflections on falsehood, and seeing equal heinousness in it whether in great or very trivial matters.
Like the fathers of his heresy, the scribes and Pharisees, he knows how to strain a gnat carefully and to swallow at one gulp the hump-backed camel laden with a weight of wickedness. But it would not be out of place to say to him, 'refrain from making such a rule in our system; cease to bid us think it of no account to measure the guilt of a falsehood by the slightness or the importance of the circumstances.' Paul telling a falsehood and purifying himself after the manner of the Jews to meet the needs of those whom he usefully deceived did not sin the same as Judas for the requirement of his treachery putting on a kind and affable look.
By a falsehood Joseph in love to his brethren deceived them; and that too while swearing 'by the life of Pharaoh;' but his brethren had really lied to him, in their envy plotting his death and then his enslavement. There are many such cases: Sarah lied, because she was ashamed of laughing: the serpent lied, tempting man to disobey and change to a divine existence. Falsehoods differ widely according to their motives. Accordingly we accept that general statement about man which the Holy Spirit uttered by the Prophet, 'Every man is a liar.' and this man of God, too, has not kept clear of falsehood, having chanced to give a place the name of a neighbouring district, through oversight or ignorance of its real name.
But Eunomius also has told a falsehood, and what is it? Nothing less than a misstatement of Truth itself. He asserts that One who always is once was not; he demonstrates that One who is truly a Son is falsely so called; he defines the Creator to be a creature and a work; the Lord of the world he calls a servant, and ranges the Being who essentially rules with subject beings. Is the difference between falsehoods so very trifling, that one can think it matters nothing whether the falsehood is palpable in this way or in that?
Source: Against Eunomius (New Advent)