This wisdom has been declared to you in terms of Sāṅkhya; now hear this regarding yoga. Endowed with which, oh Pārtha, you will abandon the bondage of karma

Doctrinal transition: sāṅkhya (philosophical analysis of the ātman as immutable) has been presented. Now yoga — the practice of action without attachment that produces liberation (karma-bandha-prahāṇa).

The wisdom (buddhiḥ) is instrument (yayā — by which). Yuktaḥ (yoked, united) with this buddhi, Arjuna prahāsyasi (will abandon) the karma-bandham (bond of action that ties to results).

Sāṅkhya gives vision; yoga gives method. We need both: understanding and practice.