KAṬHA UPANISHAD · 2.2.11

सूर्यो यथा सर्वलोकस्य चक्षुः
न लिप्यते चाक्षुषैर्बाह्यदोषैः ।
एकस्तथा सर्वभूतान्तरात्मा
न लिप्यते लोकदुःखेन बाह्यः ॥ ११॥

sūryo yathā sarvalokasya cakṣuḥ
na lipyate cākṣuṣairbāhyadoṣaiḥ ।
ekastathā sarvabhūtāntarātmā
na lipyate lokaduḥkhena bāhyaḥ ॥ 11॥

Even as the Sun is the eye of all this world, yet it is not soiled by the outward blemishes of the visual, so there is one Spirit within all creatures, but the sorrow of this world soils it not, for it is beyond grief and his danger.

Sri Aurobindo · CWSA 18, p. 122