Comments

Comm. NT: 18.
Pakiṇṇakakathāvaṇṇanā

‘Mere unification of the mind’: the kind of concentrating (samādhāna) that is undeveloped and just obtained by one in pursuit of development.
That is called ‘basic concentration,’ however, since it is the basic reason for the kinds of more distinguished concentration to be mentioned later in this connection.
This ‘mere unification of the mind’ is intended as momentary concentration as in the passage beginning, ‘I internally settled, steadied, unified and concentrated my mind’ (M I 116).
For the first unification of the mind is recognized as momentary concentration here as it is in the first of the two successive descriptions: ‘Tireless energy was aroused in me … my mind was concentrated and unified’ followed by ‘Quite secluded from sense desires …’” (M I 21)

пали	Iminā panassa ovādena niyakajjhattavasena cittekaggatāmatto mūlasamādhi vutto.
Nyanamoli thera	But what is stated in that advice is basic concentration consisting in mere unification of mind18 internally in the sense of in oneself (see Ch. XIV, n. 75).