Sage Vishwamitra's request to King Dasharatha

अहं नियममातिष्ठ सिद्धिर्यथं पुरुशर्षभ
तस्य विघ्नकरौ द्वौ राक्षसौ कामरूपिणौ
व्रते मे बहुशश्चीर्णे समाप्त्यां राक्षसाविमौ
मरीचश्च सुबाहुश्च वीर्यवंतौ सुशिक्षितौ
तौ मांसरुधिरौघेण वेदिं तामभ्यवर्शताम्
अवधूते तथा भूते तस्मिन्नियमनिश्चय
क्रुतश्रमौ निरुत्साहस्तस्माद्देशादपाक्रमे
न च मे क्रॊधमुत्स्रष्टुं बुद्धिर्भवति पार्थिव
तथाभूता हि सा चर्या न शापस्तत्रं मुच्यते
स्वपुत्रं राजशार्दूल रामं सत्यपराक्रमं
काकपक्षधरं शूरं ज्येष्ठं मे दातुमर्हसि
शक्तो ह्येष मया गुप्तो दिव्येन स्वेन तेजसा
राक्षसा ये विकर्तारस्तेषामपि विनाशने
श्रेयश्चास्मै प्रदास्यामि बहुरूपं न संशयः
त्रयाणामपि लोकानां येन ख्यातिं गमिष्यति
न च तौ राममसाध्य शक्तौ स्थातुं कथं चन
न च तौ राघवादन्यो हंतुमुत्सुहते पुमान्
वीर्योत्सिक्तौ हि तौ पापौ कालपाशवशं गतौ
रामस्य राजशार्दूल न पर्याप्तौ महात्मनः
अहं विद्धि महात्मानं रामं सत्यपराक्रमम्
वसिष्ठो अपि महातेजा ये चे मे तपसी स्थिताः

ahaM niyamamaatiShTha siddhiryathaM purusharShabha
tasya vighnakarou dwou raakShasou kaamaroopiNou
vratE mE bahushashceerNE samaaptyaaM raakShasaavimou
mareechashca subaahushca veeryavaMtou sushikShitou
tou maaMsarudhiroughENa vEdiM taamabhyavarshataam
avadhootE tathaa bhootE tasminniyamanishcaya
krutashramou nirutsaahastasmaaddEshaadapaakramE
na ca mE krodhamutsraShTuM buddhirbhavati paarthiva
tathaabhootaa hi saa caryaa na shaapastatraM mucyatE
swaputraM raajashaardoola raamaM satyaparaakramaM
kaakapakShadharaM shooraM jyEShThaM mE daatumarhasi
shaktO hyesha mayaa gupto divyenaswena tEjasaa
raakShasaa yE vikartaarastEShaamapi vinaashane
shrEyashcaasmai pradaasyaami bahuroopaM na saMshayaH
trayaaNaamapi lOkaanaaM yEna khyaatiM gamiShyati
na ca tou raamamasaadhya shaktou sthaatuM kathaM cana
na ca tou raaghavaadanyO haMtumutsuhatE pumaan
veeryOtsiktou hi tou paapou kaalapaashavashaM gatou
raamasya raajashaardoola na paryaaptou mahaatmanaH
ahaM viddhi mahaatmaanaM raamaM satyaparaakramam
vasiShThO api mahaatEjaa yE cE mE tapasee sthitaaH

Shloka Translation:
Oh the great of human beings, when I with a dedicated mind start a ritual
There are two demons who can change forms as they can, destroy that
My ritual practise is being destroyed by those dishonoured demons
By name Mareecha and Subaahu who have been well trained in valour
They rain the Meat and Blood into the holy pedestal where rituals are performed
They are the most disregarded demons who don’t have disciplined actions
Their actions create frustrations and hence they deserve to be thrown out of the region
I haven’t gone to the peak of being angry, understanding their mortal capacity
Hence I haven’t cursed them on their wrong doings
You Son is excellent amongst the kings and protects the truth
He is the prime amongst all the human warriors, hence share him with me
I know through my vision that he has a divine aura
That he can destroy the wrong doing demons individually
I’ll provide all the guidance and support, don’t doubt about it
As he will be recorded famous amongst the three worlds
I doubt you know about the impossible strength of Rama
There is no other than him in the Raghava dynasty and all of them clubbed together
Although valorous you all would be captured by the Time’s limits
Hence you all aren’t sufficient to Rama, a great soul and excellent amongst all kings
I believe that the great soul Rama is the one who fights and protects truth
Vasishtha who through his meditation vision understands about this

The above verses are available in the 18th sarga of Valmiki Maharshi’s Ramayana. Here Sage Vishwamitra asks King Dasharatha to send Rama along with him in order to kill the wicked demons who were disturbing in his rituals by throwing blood and meat into the sacred pedestial. The sage continues to praise Rama stating that he understands the valour of Rama, who has all the divine strengths and there is no match for him in the Raghava dynasty even when all the kings are clubbed together and nor does any of the beings have that strength as him. Dasharatha doesn’t understand his Son’s mighty strength. The sage is fundamentally mentioning that there is a divine power in Rama, which he can see through his meditation vision and so as the sage Vasishtha who is the Guru of King Dasharatha. He also mentions that the king shouldn’t be worried about his valour against the demons as all the support and guidance will be provided by himself to the great soul Rama. So, if one understands and reads Ramayana, we'll come to know that through his divine vision, the sage Vishwamitra understood who this Rama is and his purpose to have come into this mortal world taking a human form.