Canto 2 -
Ayodhyā-kāṇḍa
Chapter 111: Rāma Agrees to Accept the Throne After Returning to Ayodhyā
Text 2.111.6

वृद्धाया धर्मशीलाया मातुर्नार्हस्यवर्तितुम्।
अस्यास्तु वचनं कुर्वन्नातिवर्तेः सतां गतिम्॥

vṛddhāyā dharma-śīlāyā mātur nārhasy avartitum
asyās tu vacanaṁ kurvann nātivarteḥ satāṁ gatim

vṛddhāyāḥ = to Your old; dharma-śīlāyāḥ = devoted to dharma; mātuḥ = mother; na = not; arhasi = You should; avartitum = avoid personal service; asyāḥ tu = her; vacanam = words; kurvan = by carrying out; na ativarteḥ = You will not transgress; satām = of the predecessor saintly kings; gatim = the path.

You should not avoid personal service to Your old mother devoted to dharma. By carrying out her words, You will not transgress the path of the predecessor saintly kings.

Rāma should not avoid personal service to His mother because:

pituḥ śata-guṇaṁ mātā gauraveṇātiricyate

“One’s mother is a hundred times more worthy of respect than one’s father.”1

GLOSS. Rāma should not avoid personal service to His old mother, that is, He should not transgress it. 

1 The verse appears in the Bhandarkar Oriental Research Institute’s edition of Mahābhārata as a supplementary text with the number 14.4.2530.