Valmiki Ramayana Yuddha Kanda Sarga 32 Shloka 28
Original Shlokaममहेतोरनार्यायाह्यनर्हःपार्थिवात्म: । रामस्सागरमुततीर्यसत्त्ववान् गोष्पदेहतः ।।6.32.28।।
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अनर्हः undeserving, पार्थिवात्मजः son of emperor, सत्त्ववान् valiant, रामः Rama, अनार्यायाः not noble, मम my, हेतोः on account of, सागरम् ocean, उततीर्य having crossed, गोष्पदे for a footprint of cow, हतः killed.
"On account of an undeserving one, Rama, the son of the emperor, a valiant one who does not deserve to be killed, after having crossed the ocean is killed by a footprint of a cow(easily)."