Tasmat — therefore — shastram pramanam te — let shastra be your authority — in karya-akarya-vyavasthitau — the determination of what to do and what not to do. Jnatva — having known — shastra-vidhana-uktam karma — the action that shastra prescribes — kartum iha arhasi — you are fit to act here.
Krishna seals the chapter with the operative directive: shastra is the authority for action; know what it prescribes, and act accordingly.
Shankara reads the verse as a functional boundary-marker for those still in the karmabhumi — the ground of action. Shastra is pramana precisely because the aspirant cannot yet trust svabhava — one's own nature — uncorrected by repeated wrong action born of desire. The verse does not exalt shastra as final; it exalts shastra as the corrective instrument appropriate to the disciple's current stage. Once jnana has settled, what shastra prescribes flows naturally; until then, shastra is the explicit guide.
Madhusudana synthesizes both registers: the chapter's argument is that turning away from shastra — shastra-vimukhata — in favor of kama-governed action makes one unfit for all purusharthas — worldly or transcendent. Therefore shastra — defined precisely as Veda plus the smriti and Purana that depend on it, not mere personal speculation or Buddhist-style reasoning — is the single pramana for karya-akarya. The bhakta's epistemic life is anchored in this textual continuity.
Ramanuja reads shastra not as a corrective for impure aspirants but as the luminous body of testimony that reveals Purushottama and the karma that pleases Him. The Vedas, upheld by dharma-shastra, itihasa, Purana, together disclose both the nature of Bhagavan and the actions that constitute kainkarya. Knowing the tattva and the karma that pleases the Lord, the bhakta is fit to act precisely toward that end. Shastra is the Bhagavan's own self-disclosure made permanent in text.
Madhva reads shastra as pramana because Hari alone is its author and its content; svatantra Hari speaks through shastra to direct the paratantra-jiva. Knowing what is shastra-vidhana-uktam — what shastra commands — and acting accordingly is the bheda-frame's correct operational mode: the jiva's action is its dependent response to Hari's spoken will. The chapter's whole binary collapses to this directive.
Vallabha closes the chapter with a distillation: shastra-authority culminates in the single command — 'act in battle, your svadharma, with your mind given to Me.' The scripture's final meaning is not rule-compliance but reorientation of the kartri toward Krishna as the one for whom all action occurs.
Vallabha's closing verse-seal distinguishes the daivi sampat as the natural shastric obedience and the asuri as its refusal.
Shridhara holds the verse as the phala-vakya of the entire chapter: now that the daivi-asuri distinction has been established, the practical upshot is that shruti, smriti, Purana form the unified pramana-body for determining karya and akarya. One who stands in karma-adhikara — holding eligibility to act — is to act according to shastra. The chapter's whole binary moral architecture lands on this directive.