4.28 Possessions, austerity, study Krishna speaks

द्रव्ययज्ञास्तपोयज्ञा योगयज्ञास्तथापरे
स्वाध्यायज्ञानयज्ञाश्च यतयः संशितव्रताः

dravya-yajñās tapo-yajñā yoga-yajñās tathāpare
swādhyāya-jñāna-yajñāśh cha yatayaḥ sanśhita-vratāḥ

Some offer their possessions; some their austerity; some their practice; and some, holding to their vows, offer their study and their knowledge.

Explanation

Possessions, austerity, practice, study.

Four more kinds, and the last is knowledge itself offered by those holding to their vows.

Knowledge appears in this chapter as the fire, as the offering, and as the thing gained — a triple role like 13.18's collapse of knower, known and knowing into one.

Word by word

dravya-yajñāḥ: offering one’s own wealth as sacrifice
tapaḥ-yajñāḥ: offering severe austerities as sacrifice
yoga-yajñāḥ: performance of eight-fold path of yogic practices as sacrifice
tathā: thus
apare: others
swādhyāya: cultivating knowledge by studying the scriptures
jñāna-yajñāḥ: those offer cultivation of transcendental knowledge as sacrifice
cha: also
yatayaḥ: these ascetics
sanśhita-vratāḥ: observing strict vows