Bhashya
निष्ठा गुरुशुश्रूषादितत्परत्वं ब्रह्मविज्ञानाय ॥
In plain words
Steadfast dedication, starting with devoted service to the teacher, leads directly to the realization of Brahman.
Close to the Sanskrit
Firm dedication, beginning with service to the guru, is for the direct realization of Brahman.