Katha Upanishad Verse 2.3.14
Liberation is not exclusive to a post-mortem state. When all the desires and attachments that cling to the human heart are surrendered, the mortal becomes immortal even here and now, attaining the state of Brahman.
Sanskrit Verse
यदा सर्वे प्रमुच्यन्ते कामा येऽस्य हृदि श्रिताः ।
अथ मर्त्यो’मृतो भवत्यत्र ब्रह्म समश्नुते ॥ १४ ॥
Transliteration
yadā sarve pramucyante kāmā ye’sya hṛdi śritāḥ |
atha martyo’mṛto bhavatyatra brahma samaśnute || 14 ||
Translation
When all desires clinging to the heart of one fall off, then the mortal becomes immortal and here attains Brahman.

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