Canto 2 -
Ayodhyā-kāṇḍa
Chapter 111: Rāma Agrees to Accept the Throne After Returning to Ayodhyā
Text 2.111.13

इह मे स्थण्डिले शीघ्रं कुशानास्तर सारथे।
आर्यं प्रत्युपवेक्ष्यामि यावन्मे न प्रसीदति॥

iha me sthaṇḍile śīghraṁ kuśān āstara sārathe
āryaṁ pratyupavekṣyāmi yāvan me na prasīdati

iha = here; me = with Me; sthaṇḍile = on the ground; śīghram = quickly; kuśān = kuśa grass; āstara = spread; sārathe = charioteer; āryam = noble brother; pratyupavekṣyāmi = I will protest; yāvat = until; me = My; na prasīdati = becomes pleased.

Charioteer, quickly spread kuśa grass on the ground here. I will protest until My noble brother becomes pleased with Me.

He wanted the kuśa grass to be spread to invoke purity.

Therefore, we will come across this statement:

tataḥ sāgara-velāyāṁ darbhān āstīrya rāghavaḥ
añjaliṁ prāṅ-mukhaḥ kṛtvā prati śiśye mahodadheḥ

“Then Rāghava spread kuśa grass with sharp edges on the shore of the ocean, joined His palms in supplication while facing the east and then lay down facing the great ocean.” (Rāmāyaṇa 6.21.1)