The dating here is straightforward in a way that little else in this collection is.
The text appears in the Sutta Nipata, which is generally regarded as among the oldest strata of the Pali canon on linguistic grounds, it preserves metrical and grammatical forms archaic relative to the prose discourses, and again in the Khuddakapatha, a short collection used for teaching novices. Nothing about it is disputed in the way authorship and composition are disputed for most of the material here. It is early Buddhist, it is canonical in the Theravada, and versions of it exist in other early Buddhist textual traditions.
Its modern reception has been unusually smooth as well. It translates well, requires no doctrinal background to be moved by, and contains nothing a secular reader must bracket. It has consequently become one of the two or three Buddhist texts most likely to be encountered in a Western context, read at funerals, printed on cards, and taught in secular mindfulness programmes that otherwise avoid canonical material.
There is a small cost to that. The sutta's opening lines are conditions: it addresses one who has already undertaken a particular discipline, and the list of qualities at the start is not decorative preamble but the ground the aspiration stands on. Extracting the mother-and-child image alone, which is what usually happens, produces a sentiment rather than an instruction.
The Pali is also more austere than most English versions suggest. The sustained warmth is genuinely there; the sweetness is often added in translation.