Ramayana 2.113.10

पितुः प्रतिज्ञां तामेव पालयिष्यामि तत्त्वतः।चतुर्दश हि वर्षाणि या प्रतिज्ञा पितुर्मम।।।।

pituḥ pratijñāṃ tām eva pālayiṣyāmi tattvataḥ | caturdaśa hi varṣāṇi yā pratijñā pitur mama ||

Truly, I shall uphold that very pledge of my father in full truth—the promise of fourteen years.