Bg 18.23

niyataṁ saṅga-rahitam
arāga-dveṣataḥ kṛtam
aphala-prepsunā karma
yat tat sāttvikam ucyate
Synonyms: 
niyatam — regulated; saṅga-rahitam — without attachment; arāga-dveṣataḥ — without love or hatred; kṛtam — done; aphala-prepsunā — by one without desire for fruitive result; karma — action; yat — which; tat — that; sāttvikam — in the mode of goodness; ucyate — is called.
Translation: 
That action which is regulated and which is performed without attachment, without love or hatred, and without desire for fruitive results is said to be in the mode of goodness.
Purport: 

Regulated occupational duties, as prescribed in the scriptures in terms of the different orders and divisions of society, performed without attachment or proprietary rights and therefore without any love or hatred, and performed in Kṛṣṇa consciousness for the satisfaction of the Supreme, without self-satisfaction or self-gratification, are called actions in the mode of goodness.