Bhagavad Gita 17.25तदित्यनभिसन्धाय फलं यज्ञतपःक्रियाः।दानक्रियाश्च विविधाः क्रियन्ते मोक्षकाङ्क्षि ॥

With Tat With the utterance of the word Tat (That).Phalam Fruit of sacrifice, austerity and charity.Danakriyah Acts of charity such as gifts of land, gold, rice, clothes, etc.The immortal Soul which transcends the whole world, the three Gunas, the three bodies, the three,states of waking, dreaming and deep sleep, which illumines everything, which is the basis of all, and the source of everything is connoted by the word Tat. The sages and the aspirants meditate on Tat. They utter the word Tat and say, May all our actions and the fruits of them be in the name of Tat (That or Brahman).Thus they offer all actions and their fruits to Brahman and practise renunciation. They are freed from egoism and the bondage of Karma. They attain Selfrealisation through purity of heart caused by selfless, motiveless and desireless actions.The actions that is ennobled and sanctified by uttering Om at the beginning and which is offered to That is transformed into the nature of Brahman. All actions in their entirety, O Arjuna, culminate in wisdom (IV.33). He who does the actions with the spirit of sacrifice becomes Brahman eventually.Tat is symbolic of the presentation of all the fruits of all such activities to Brahman. If you utter Tat, it is tantamount to saying, They are nt mine