I. Sagatha Vagga
Pañcalacanda the Deva's Son
Translated from the Pali by Thanissaro Bhikkhu.
Provenance, terms and conditons
The first verse in this discourse focuses on jhana as a crucial element in the path to release. The Buddha's "awakening to jhana" apparently refers to two points in his career as a bodhisatta: (1) the point when, realizing the futility of self-torture, he surmised that jhana might form the path to awakening; and (2) his realization of the extent to which jhana actually could lead to the knowledge that yielded in full awakening. (For details on both of these points, see MN 35.) In the second verse, the Buddha expands on Pañcalacanda's understanding of the practice of jhana by pointing out that it has to be endowed with mindfulness to be genuinely right concentration. This point is related to the fact that the various lists of activities constituting the path such as the five faculties, the seven factors for awakening, and the noble eightfold path always place right mindfulness before right concentration. It's also related to the statement in MN 44 that the four satipatthanas establishings of mindfulness or frames of reference form the nimitta, or theme, of right concentration.
AN 9.42 contains an explanation of the first verse here, in which Ven. Ananda identifies the first jhana as the opening offering escape from the confining place of sensual pleasures, and each successive level of jhana as the opening offering escape from the confining place of the preceeding jhana. Finally, he says, the cessation of perception and feeling acts as the ultimate opening offering escape from all forms of confinement.
Truly in a confining place, he found an opening
the one of extensive wisdom,
the awakened one who awakened to jhana, the chief bull, withdrawn,
[The Buddha:] Even in a confining place they find it,
[Pañcalacanda, said the Blessed One,]
the Dhamma for the attainment of Unbinding.
Those who have gained mindfulness
are rightly well-centered.
 In The Connected Discourses of the Buddha (CDB), this phrase is translated as "who discovered jhana," but the verb is abuddhi: "awakened to."
 In CDB, this sentence is translated as a continuation of the preceding one: "those who have acquired mindfulness, those perfectly well concentrated." However, the Pali is constructed of two clauses in the ye ... te ... format that constitutes a separate sentence.