Valmiki Ramayana Ayodhya Kanda Sarga 24 Shloka 33
Original Shlokaगच्छ पुत्र त्वमेकाग्रो भद्रं तेऽस्तु सदा विभुः। पुनस्त्वयि निवृत्ते तु भविष्यामि गतव्यथा।।2.24.33।।
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पुत्र O Son त्वम् you, एकाग्रः with resolute mind, गच्छ go, विभुः god, ते to you, सदा always, भद्रम् safety, अस्तु be it, त्वयि when you, पुनः again, निवृत्ते तु on your coming back, गतव्यथा relieved of suffering, भविष्यामि I shall become.
Go with a steadfast mind, O my son May god be gracious. Only with your return, I shall be relieved of my suffering.