The word "Dhamma" in this phrase can also be translated as little d "dhamma", signifying phenomenon. However, the way it is worded in this translation (whose translation is it?) has been rendered in such a way that it precludes the (little d) "dhamma" interpretation.
I believe this is referring to non-becoming, particularly applied during meditation practice. We should let go of fine-states of becoming, to say nothing of the coarser states.
"Having understood name-and-form, which is a product of prolificity,
And which is the root of all malady within and without,
He is released from bondage to the root of all maladies,
That Such-like-one is truly known as 'the one who has understood'." (Snp 3.6)
"Whether I were to preach in brief, Sāriputta, or whether I were to preach in detail, Sāriputta, or whether I were to preach both in brief or in detail, Sāriputta, rare are those who understand." (A I 333, Sāriputtasutta)