KAṬHA UPANISHAD · 2.3.15

यदा सर्वे प्रभिद्यन्ते हृदयस्येह ग्रन्थयः ।
अथ मर्त्योऽमृतो भवत्येतावद्ध्यनुशासनम् ॥ १५॥

yadā sarve prabhidyante hṛdayasyeha granthayaḥ ।
atha martyo’mṛto bhavatyetāvaddhyanuśāsanam ॥ 15॥

When all the strings of the heart are rent asunder, even here in this human birth, then the mortal becometh immortal. This is the whole teaching of the Scriptures.