यः सर्वेषु भूतेषु तिष्ठन्सर्वेभ्यो भूते-भ्योऽन्तरो यं सर्वाणि भूतानि न विदु-र्यस्य सर्वाणि भूतानि शरीरं यः सर्वा-णि भूतान्यन्तरो यमयत्येष त आत्मा-न्तर्याम्यमृत इंत्यधिभूत मथाध्यात्मम् ॥
In plain words
The one who lives inside every single being, yet is nothing any being can claim as its own, whom no being anywhere knows, whose body all of them together are, who governs every one of them from within -- that is your self, the ruler seated inside everything, and death does not touch him. So much for beings. Now for the self within your own body.
Close to the Sanskrit
He who, dwelling in all beings, is other than all beings, whom all beings do not know, whose body all beings are, who controls all beings from within -- he is your self, the inner controller, immortal. Thus the teaching regarding beings; now the teaching regarding the individual self.