Valmiki Ramayana Ayodhya Kanda Sarga 54 Shloka 15

दृढव्रतः of firm resolve, भ्राता brother, अनुजः younger, प्रियः dear, अयं सौमित्रिः this son of Sumitra, पित्रा by father, प्रव्राज्यमानम् being sent on exile, माम् me, वनमेव to the forest, अन्वगमत् followed.

This is the son of Sumitra, my beloved younger brother, a man of firm resolve. He has accompanied me when I was sent on exile to the forest by my father.