Shiva Purana

siva.sh/siva-purana/rudra-samhita/143/37

यावत्स्वस्थमिदं वर्ष्म यावन्नेन्द्रियविक्लवः ।। यावज्जरा च दूरेऽस्ति तावत्सौख्यं प्रसाधयेत् ।।३७।।

sanskrit

One shall seek and enjoy happiness as long as the body is hale and hearty, as long as the sense-organs are not impaired and as long as the old age is far off.

english translation

yAvatsvasthamidaM varSma yAvannendriyaviklavaH || yAvajjarA ca dUre'sti tAvatsaukhyaM prasAdhayet ||37||

hk transliteration by Sanscript