B.G 3.28

तत्त्ववित्तु महाबाहो गुणकर्मविभागयोः। गुणा गुणेषु वर्तन्त इति मत्वा न सज्जते ॥२८॥

tattvavittu mahābāhō guṇakarmavibhāgayōḥ। guṇā guṇēṣu vartanta iti matvā na sajjatē ॥28॥

[ तत्त्ववित् तु महा-बाहो गुण कर्म विभागयोः। गुणा गुणेषु वर्तन्त इति मत्वा न सज्जते॥
tattvavit = knower of the principles; tu = but; mahā-bāhō = O mighty-armed one; guṇa karma vibhāgayōḥ = one who knows how to differentiate the types of qualities and actions; guṇā = the qualities; guṇēṣu = the topics of qualities; vartanta = engage; iti = thus; matvā = Understanding; na = not; sajjatē = gets attached;]

But O Mighty armed, he who has the ability to differentiate the different types of qualities and actions is the knower of principles. Understanding the qualities (of five senses, five organs, and the mind) engage themselves in their respective topics, he does not get attached.

Gīta Bhāshya 3.28

tattvavit - one who has the ability to differentiate between different types of qualities and actions; guṇā - qualities of the Indriyas (i.e. qualities of five senses, five actions and the mind); guṇēṣu - respective topics that the Indriyas engage in;

कर्मभेदस्य गुणभेदस्य च तत्त्ववित्। गुणाः इंद्रियादीनि। गुणेषु विषयेषु ॥२८॥

karmabhēdasya guṇabhēdasya ca tattvavit। guṇāḥ iṁdriyādīni। guṇēṣu viṣayēṣu ॥28॥

[karmabhēdasya = by differentiatio of actions; guṇabhēdasya = by differentiations of qualities; ca = and; tattvavit = one becomes the knower of principles; guṇāḥ = 'guṇāḥ' refers; iṁdriyādīni = to Indriyas i.e. five sense functions, five action functions, and the mind; guṇēṣu = 'guṇēṣu' refers to; viṣayēṣu = topics of the senses;]

One becomes the knower of principles by differentiating actions and their respective qualities. 'guṇā' refers to qualities of the Indriyas (i.e. qualities of five senses, five actions and the mind). 'guṇēṣu' refers to respective topics that the Indriyas engage in.