Chandogya Upanishad 1.9.4

1.9.4

tathāmuṣmiṃl loke loka iti \
sa ya etam (S ) vidvān upāste parovarīya eva (S ) loke jīvanaṃ bhavati tathāmuṣmiṃl loke loka iti loke loka iti \\109.4\

3. When Atidhanvan Śaunaka told this Udgītha to Udaraśāṇḍilya, he also said: "As far as they shall know this Udgītha among your offspring, so far will they have the most excellent life in this world, and likewise a world in yonder world." He who knows and reverences it thus has the most excellent life in this world, and likewise a world in yonder world—yea, a world in yonder world.'