Canto 2 -
Ayodhyā-kāṇḍa
Chapter 61: Kausalyā Condemns Daśaratha in Extreme Distress
Text 2.61.7

महेन्द्रध्वजसंकाशः क्व नु शेते महाभुजः।
भुजं परिघसंकाशमुपधाय महाबलः॥

mahendra-dhvaja-saṅkāśaḥ kva nu śete mahā-bhujaḥ
bhujaṁ parigha-saṅkāśam upadhāya mahā-balaḥ

mahā-indra-dhvaja-saṅkāśaḥ = He resembles a rainbow; kva nu = where does Rāma; śete = and sleep; mahā-bhujaḥ = He is mighty-armed; bhujam = His arms; parigha-saṅkāśam = [while] His arm resembles a metal rod; upadhāya = place; mahā-balaḥ = of great strength.

Where does Rāma place His arm and sleep? He is mighty-armed, of great strength. He resembles a rainbow [while] His arm resembles a metal rod.

[Authorities] say that sometimes the rainbow appearing like a flag signals [the appearance of] great prosperity.