Valmiki Ramayana Ayodhya Kanda Sarga 105 Shloka 24
Original Shlokaनन्दन्त्युदित आदित्ये नन्दन्त्यस्तमितेऽहनि। आत्मनो नावबुध्यन्ते मनुष्या जीवितक्षयम्।।2.105.24।।
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मनुष्याः people, आदित्ये the Sun, उदिते rises, नन्दन्ति rejoice, रवौ when the Sun, आस्तमिते sets, नन्दन्ति rejoice, आत्मनः their own, जीवितक्षयम् decline of life span, नावबुद्ध्यन्ते are not aware of.
People rejoice when the Sun rises and rejoice when the Sun sets. But they are unaware of the decline of the life span of their own.