Aitareyabrahmana 1.6

1.6

Moreover, this metre, the virāj, possesses five virilities.
In that it has three feet, thereby it is the uṣṇih and the gāyatrī; in that its feet consist of eleven syllables, thereby it is the triṣṭubh; in that it consists of thirty-three syllables, thereby it is the anuṣṭubh.
Indeed, metres do not fail because of one syllable, nor because of two.
In that it is the virāj, that is the fifth.
He secures the virility of all metres;
he attains the virility of all metres;
he attains union, identity of form, and the same world with all metres;
he becomes an eater of food, a lord of food;
he attains food along with offspring, who, knowing thus, makes the two [verses] in the virāj.
Therefore, the two should be made in the virāj alone,
[namely], 'preddho agne...' and 'imo agne...'.
Consecration is truth-order (ṛta); consecration is truth (satya). Therefore, only truth should be spoken by the consecrated sacrificer.
Now indeed they say:
'What man is capable of speaking the whole truth?
For the gods are united with truth, and men are united with falsehood.'
He should speak speech that contains the word vicakṣaṇa ('discerning').
The eye is discerning, for by it one sees distinctly.
This indeed is the truth placed among men, namely the eye.
Therefore, of one who relates [something], they say:
'Did you see [it]?' If he says, 'I saw [it]', then they believe him.
And if he sees it himself, he does not believe even many others.
Therefore, he should speak speech that contains the word vicakṣaṇa; his speech indeed becomes spoken with truth as its highest.