Valmiki Ramayana Ayodhya Kanda Sarga 52 Shloka 35
Original Shlokaयथा च तव कैकेयी सुमित्रा च विशेषतः। तथैव देवी कौशल्या मम माता विशेषतः।।2.2.35।।
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तव your, कैकेयी Kaikeyi, यथा च just as, सुमित्रा च Sumitra also, विशेषतः in a special manner, देवी Devi, sumitra विशेषतः specially, मम माता my mother, कौशल्या Kausalya, तथैव in the same way.
Just as you treat Kaikeyi and Sumitra in a special manner, so should you treat Devi Kausalya, my mother.