Valmiki Ramayana Ayodhya Kanda Sarga 11 Shloka 8
Original Shlokaआत्मना वात्मजैश्चान्यैर्वृणेयं मनुजर्षभम्। तेन रामेण कैकेयि शपे ते वचनक्रियाम्।।2.11.8।।
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कैकेयि Kaikeyi, आत्मना वा by myself, अन्यैः by others, आत्मजैश्च my sons, यम् whom, मनुजर्षभम् best among men, वृणे I choose, तेन रामेण by that Rama, ते your, वचनक्रियाम् to fulfil your wish, शपे swear.
O Kaikeyi I wish the best among men Rama well.Even at the expense of my life or the lives of the rest of my sons I swear in his name I shall fulfil your wish.