1 Gita Sloka Every Day - Chapter 18 - Moksha Sanyasa Yoga - Sloka 18

The entire content of this mail is from Shri V N Gopala Desikan's  Srimad Bhagavad Gita, published by Vishishtadvaita Research Centre, Chennai and The Bhagavad Gita by Swami Chidbhavananda published by Ramakrishna Mission

The Three Gunas Give Impetus to Karma - 18-40

1 Gita Sloka  Every Day - Chapter 18 - Moksha Sanyasa Yoga - Sloka 18

Thirumangai Alwar

Jnanam jneyam parigyata trividha karma chodana I

Karanam karma karta  iti trividhah karma sangrahah II sloka 18

ज्ञानं ज्ञेयं परिज्ञात त्रिविधा कर्म चोदना i 

करणं कर्म कर्ता इति त्रिविधः कर्म संग्रहः ई श्लोक 18

Knowledge, the object of knowledge and the knower form the threefold incitement to action; and this instrument, the object and the agent are the three fold constituents of action. 

An inducement to work  (karma) consists of three parts - (1) knowledge about the work to be done (2) the work itself (3) the knower of the work , the one who understands it.

Of these the middle one, ie., the work itself, has again three parts - (1) the means by which the work is performed, like the materials required for it (2) the work itself like the yagna and  (3) the doer who performs the yagna etc.