Yōga Sūtra 2.23

svasvāmiśaktyōḥ svarūpōpalabdhihētuḥ saṁyōgaḥ।

The understanding of the essence of one's own self, and that of the master, and the understanding of both their powers, is obtained by Samyōga, i.e. in-unison.

Difference between 'sva', the self, and Svāmi, the master, is to be observed.