I have been afraid, and would like to call it truth that I have been afraid of, and certainly fear lies so it is difficult to disagree with the implicit truth of the statement.

The question becomes, what is the character of this theoretical person being described? Is it a man at all or “the man” in a very imperative sense?

To fear no truth may also be to fear no illusion, to fear no absence of truth. In that sense the character of this man is that he is unconcerned with truth; that the word means nothing to him.

Yet as I see it, a word is not a word without meaning. This is not what the quotation appears to disagree with at first glance.

Clearly one way I may be mistaken is that he is speaking of “truths” in reference to specific perceivable standpoints, rather than “truth” in a general sense such as “truthfulness”. Obviously the man who does not fear truthfulness has much to fear from lies, if this means he is gullible.

On the other hand, if his fearlessness is of the truth of any given statement this may reflect an apprehending rather than apprehension of meaning. Although this does suggest that there would be nothing to fear from lies, it also suggests that the man does not fear himself. Yet one would suspect the man who fears no truths would be someone to fear, and perhaps more so to know himself well. Does this imply that he lies to himself? Or the lie he fears is that which conceals his knowledge of himself?

Indeed, self-awareness can be terrifying. There must be a theatrical viewpoint on “within and without”. Perhaps what (presumably Jefferson) is implying is simply that reason, in an enlightenment sense, is achieved insofar as one is true, to the extent that one would not fear it. It is almost redundant then to say that there is nothing to fear from lies, since reason already has dismissed them.

Sometimes I’m bothered by expressions that don’t make sense until they’re redundant.

I know this is really a little beyond bounds to go on like this, but I have loose energy and nothing to do with it, so this seems healthy enough.

Perhaps one good translation would be
“the man who does not bely will not lie to honest men”.

(The sense I had of the word bely was that it meant more strictly fanciful usage or implication rather than outright deceit. The poetic sense. None of the online dictionaries seem to be in agreement with this. Etymologically, “bely” may be translated as “to make beautiful” rather than “to make deceit”.)