Canto 2 -
Ayodhyā-kāṇḍa
Chapter 111: Rāma Agrees to Accept the Throne After Returning to Ayodhyā
Text 2.111.11

स हि राजा जनयिता पिता दशरथो मम।
आज्ञातं यन्मया तस्य न तन्मिथ्या भविष्यति॥

sa hi rājā janayitā pitā daśaratho mama
ājñātaṁ yan mayā tasya na tan mithyā bhaviṣyati

saḥ hi = he is; rājā = King; janayitā = begot Me; pitā = father; daśarathaḥ = Daśaratha; mama = My; ājñātam = had promised; yat = what; mayā = I; tasya = him; na = not; tat mithyā bhaviṣyati = will go in vain.

King Daśaratha begot Me. He is My father. What I had promised him will not go in vain.

King Daśaratha was not Rāma’s adoptive father.

Lord Rāma implies here that since He had first promised His father, He could not carry out the instructions of His mother or brother.1

1 He could do so only after fulfilling His father’s instruction.