Valmiki Ramayana Kishkindha Kanda Sarga 41 Shloka 45
Original Shlokaअन्ते पृथिव्या दुर्धर्षास्तत्र स्वर्गजितः स्थिताः। ततः परं न वस्सेव्यः पितृलोक स्सुदारुणः।।4.41.45।।
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ततः then, पृथिव्याः the earth, अन्ते at the end, दुर्धर्षाः unassailable, स्वर्गजितः those who had conquered heaven, स्थिताः stay in, ततःपरम् beyond that place, सुदारुणः dreadful, पितृलोकः world of the deceased ancestors, वः for you, सेव्यः possible to enter, नः not.
'The divine people who have earned a place in heaven stay there at the end of their life on earth. Beyond, lies the dreadful world of deceased ancestors. It is not possible for you to enter that place.