Valmiki Ramayana Ayodhya Kanda Sarga 2 Shloka 45
Original Shlokaनास्य क्रोधः प्रसादश्च निरर्थोऽस्ति कदाचन।।2.2.45।। हन्त्येव नियमाद्वध्यानवध्ये न च कुप्यति।
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अस्य his, कोप: anger, प्रसादश्च favour also, कदाचन ever, निरर्थ(क): in vain, नास्ति is not, नियमात् in accordance with justice, वध्यान् those who deserve to be killed, हन्ति एव is punishable, अवध्ये those who should not be killed, न कुप्यति does not get angry.
His anger or favour never goes in vain. He kills those who rightly deserve to be killed and flares not at those whose life is to be spared.