V9.31 is the confirmation-and-assurance verse that follows V30's radical grace declaration. Its structure is elegant: (1) kṣipraṃ bhavati dharmātmā = the organic transformation that follows V30's reception; (2) śaśvac-chāntiṃ nigacchati = the quality of that transformation's result (eternal, not temporary peace); (3) kaunteya pratijānīhi = Krishna's extraordinary instruction to Arjuna to be the proclaimer of the guarantee; (4) na me bhaktaḥ praṇaśyati = the guarantee itself. The kṣipram (quickly) is philosophically precise: it distinguishes bhakti-transformation from the gradual purification model of jñāna-yoga (long study and reflection) or the progressive discipline of karma-yoga (repeated right action over time). The bhakti orientation change (ananya-bhāk = undivided devotion) produces kṣipram dharmātmā because the transformation comes from the inside out — from the fundamental orientation change, not from accumulating good behaviors. When the root changes (V30's samyag vyavasita = right resolve), the branches change quickly. The dharmātmā compound: dharma + ātmā = 'one whose soul/self (ātmā) IS dharma.' This is not 'one who follows dharmic rules' but 'one whose deepest identity is dharmic.' The bhakti orientation of V29-V30 produces this identity-level transformation. The pratijānīhi is the verse's most philosophically interesting element. Krishna does not say 'I declare it' — He says 'you declare it' (imperative to Arjuna). This recruits Arjuna as witness-teacher in the Gita's own text. The Gita will be recorded and taught because Arjuna declared what Krishna revealed. V31 makes Arjuna a co-guarantor of the teaching. This is preparation for V18.73 where Arjuna says 'naṣṭo mohaḥ smṛtir labdhā' — 'the delusion is gone, I have recovered memory' — the moment when the transformation Krishna promised in V31 is complete in Arjuna himself.