Valmiki Ramayana Ayodhya Kanda Sarga 14 Shloka 11

निर्विशङ्कया without fear or hesitation, कैकेय्या by Kaikeyi, एवम् in this way, प्रचोदितः having been urged, राजा king, बलिः emperor Bali, इन्द्रकृतं यथा like the one employed by Indra (through Vamana), पाशम् noose (promise), मोक्तुम् to release, नाशकत् was not able.

In this way urged by Kaikeyi without fear or hesitation, he (Dasaratha), like Bali unable to release himself from the noose cast by Indra (through Vamana), could not get out of the noose of promise.