“There is no meditative concentration for him who lacks insight, and no insight for him who lacks meditative concentration. He in whom are found both meditative concentration and insight, indeed, is close to Nibbana.”
Now, if I’ve understood correctly, classical Theravada explains that one can very well have meditative concentration without having wisdom, because, for example, jhâna can be achieved by concentrating on an unreal concept (like conceptual breath), without concentrating on a reality.
If my memory is correct, the Pali term in the verse is “Panna(wisdom)” , not "Vipassana(insight).
As I remember it is something like the below.
There are types of wisdoms related to each Virtue other than the wisdom.
Eg: Wisdom of Dana, Wisdom of Sila, Wisdom of Jhana etc.
It is needed to have the relavent type of wisdom in order to have each virtue like Dana, Sila, Samadhi etc.
But these wisdoms are not enough to complete Vipassana wisdom.
In that sense we can say,
There is no Sila for him who lacks Panna, and no Panna for him who lacks Sila.
So the same thing is said regarding jhana.
Even in the NaCetanakaraniya sutta it is said that "No need of an effort to achieve samadhi for the one who have completed Sila ". This is also interpreted by classical scholars as “no need of an effort to enter into the beginning of the Samadhi, but further effort is needed to complete the Samadhi”
And the Seven Visuddhis of Ratavinnita sutta also says the completion of first visuddhi drags the person up to the beginning of the second visuddhi but not up to the ending of the second visuddhi. Just like a journey by seven vehicles.
There is much understanding - Pañña - needed for mundane jhâna.
Without pañña one can/will mistake akusala concentration for the kusala type.
But as you say the object of mundane jhana is a concept, so it is not that special type of wisdom that arises with sati and momentary concentration. The latter type understands the nature of the reality that is the object at those moments.
Classical Theravada looks at the commentary.
Carter has a breakdown of the verses according to the commentary.
We should also look at the story sambahulabhikkhuvatthu but it just talks about the importance of meditation and listening to the dhamma.
There is a book written by Carter (make sure you get the red cover book… hint it is really expensive).
This has the explanation to the dhp by grammar and meaning.
Jhāna based on a kasina also has paññā (it must be included), and because samādhi is a requisite for pañña then we can see a two way relationship
It could very well be referencing the Jhāna that has Nibbāna as the object. Here everything would make sense. That of Path and Fruition. There are 89 types of consciousness but there are also 121 in the expanded form. This is referencing the 40 path fruitions (4 jhāna each).
There is no meditative absorption: natthi jhānam
For one who lacks insight, which is concomitant with enterprise and which generates meditative-absorption, there is no meditative-absorption.
Translation, Transliteration, and Commentary
There is no insight: paññā natthi
For one who is not meditating, there is not that insight whose characteristics are thus stated: “The bhikkhu who is integrated [of mind] understands and sees reality as it is.”
In whom there is meditative absorption and insight: yamhi jhānam ca paññā ca
That person in whom both of these exist indeed is standing near Nibbana. That is the meaning.