Valmiki Ramayana Kishkindha Kanda Sarga 35 Shloka 6
Original Shlokaसुदुःखं शयितः पूर्वं प्राप्येदं सुखमुत्तमम्। प्राप्तकालं न जानीते विश्वामित्रो यथा मुनिः।।4.35.6।।
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पूर्वम् earlier, सुदुःखं शयितः sleeping unhappily, उत्तमम् best, इदम् this, सुखम् happiness, प्राप्य having obtained, विश्वामित्रः Visvamitra, मुनिः यथा like the sage, प्राप्तकालम् time to attend to his duty, न जानीते I did not know.
'Sleep did not come to him in deep distress in the past, and now that great happiness has come, he does not realize that it is time to act (search for Sita). He behaves like sage Viswamitra.