Bhagavad Gita

ಕರ್ಮ ಬ್ರಹ್ಮೋದ್ಭವಂ ವಿದ್ಧಿ ಬ್ರಹ್ಮಾಕ್ಷರಸಮುದ್ಭವಮ್ ।
ತಸ್ಮಾತ್ ಸರ್ವಗತಂ ಬ್ರಹ್ಮ ನಿತ್ಯಂ ಯಜ್ಞೇ ಪ್ರತಿಷ್ಠಿತಮ್ ॥೧೫॥
karma brahmodbhavaṃ viddhi brahmākṣarasamudbhavam |
tasmāt sarvagataṃ brahma nityaṃ yajñe pratiṣṭhitam ||15||

Gist of the sloka:
Karmas originate from the Lord. Lord is obtained by following the Veda's. Therefore, Lord is always present in the yagna.
The Veda's indicate the exact way the karmas/yagna have to be performed. The yagna in turn, is the form of worship of the Lord. Lord is present everywhere and in every object. Lord also being present in the yagna, receives our worship and blesses us with the right knowledge and with performance of right karmas, leads us to mukthi.