Vishnu sahasranamam, slok 43

Slok43:       Ramo viramo virajo margo neyo nayo nayah 
                     Veero Sakthimatam  Sresto  Dharmo  Dharma ViDuttamaha

The Rama, the Cosmic Existance, the Guide, the Friend, the Cure, Curer,  the valiant, the  Supreme Energy,  the Best, the Personified Rightuousness, the  best knower of Rightuousness ( the Justice),is Vishnu. 

Here, in this slok, RamAvatAr is emphasysed.
Sree Rama of ThrethAauga, is the  incornation of Sree Maha Vishnu. 
The great Archer Sree Rama, with his valour  established the rightuousness
by killing the unrightuous.     

"Ramo sathyavan dharmavan vigrahaha"
This is what Sree Rama was, says the main slok of RamayaNa. 
Sree Rama is the personified "Truth and Rightuousness." 

Om Vishnave namaha