Eric Ormsby in The New Criterion:
Not surprisingly for “one acquainted with the night,” Robert Frost cultivated a lifelong penchant for dark sayings. These sayings included aphorisms and maxims, apothegms and proverbs, wise saws and the occasional bon mot, alongside interjections, exclamations, and guffaws, interrupted thoughts and broken utterances. They were dark because they riddled, sometimes as much by their sound as by their content. Many, of course, made their way into his finest poems. “Good fences make good neighbors” is the obvious example, but the closer you look the more you find. So strong is this tendency in Frost’s poetry that even his less aphoristic lines have taken on a lapidary sheen. “And miles to go before I sleep,” though hardly an aphorism, is often intoned as though it were. These dark sayings of our own Heraclitus of New Hampshire have by now become so familiar as to appear immemorial folk wisdom. And yet, clad in cunning homespun though they are, they conceal contradictory flashes of wit as well as mischief. Like the milkweed pod with its “bitter milk,” of which he wrote so memorably, their rough husks hold hidden, and sometimes ticklish, silks.
Now, with the publication of his Notebooks, we can gauge just how fundamental such fragmented wisdom was to Frost’s own peculiar cast of mind.
More here.
