17.27 यज्ञे in sacrifice, तपसि in austerity, दाने in gift, च and, स्थितिः steadiness, सत् Sat, इति thus, च and, उच्यते is called, कर्म action, च and, एव also, तदर्थीयम् in connection with these or for the sake of the Supreme, सत् Sat, इति thus, एव even, अभिधीयते is called.

Commentary:
If you perform sacrifice, austerity, gift and all actions in a spirit of total surrender to the Lord or the Eternal Being with purity and sincerity of heart, you will attain the highest goal of life or immortality, freedom and eternal bliss. If you do them in the name and for the sake of Brahman you will attain perfection and supreme peace of the Absolute.If you pin your faith on the glory and power of this name Om or Om Tat Sat, you will be freed from the bondage of birth and death. If you perform any sacrifice, austerity or charity or any action in a selfless and motiveless spirit, surrendering all the actions and their rewards to the Lord and if you utter the word Sat with faith, feeling and devotion, you will attain perfection and success in the action.Even the imperfect and nonSattvic acts of sacrifice, austerity and gift will be turned into perfect and Sattvic ones.These Sacrifice, austerity and gift.