Isha Upanishad Verse 7
Sanskrit Verse
यस्मिन् सर्वाणि भूतानि आत्मैवाभूद् विजानतः ।
तत्र को मोहः कः शोक एकत्वमनुपश्यतः ॥७॥
Transliteration
yasmin sarvāṇi bhūtānyātmaivābhūdvijānataḥ,
tatra ko mohaḥ kaḥ śoka ekatvamanupaśyataḥ.
Sri Aurobindo's translation
He in whom it is the Self-Being that has become all existences that are Becomings, for he has the perfect knowledge, how shall he be deluded, whence shall he have grief who sees everywhere oneness?

Muni's Play