Some make an offering of material things, some of austerity, and others of yoga; others again make an offering of scriptural study and of knowledge — all of them striving ascetics, firm in their vows.
Explanation
Krishna is continuing his list of the many kinds of sacrifice (yajña), meaning disciplined acts of offering, that people practise. Here he names giving of wealth (dravya), austerity (tapas), yoga, and the study of scripture (svādhyāya) along with the pursuit of knowledge (jñāna). The common thread is that each is done with strict commitment (vrata), as a way of offering oneself.