Verse three of the Ramayana Chaupai
Bhir pari jab bhagt pukare, door karo Prabhu dukh hamare
O the one to who the devotees crowd and cry "O Lord remove our miseries"
Dashrath ke ghar janme Ram
in Dashrath's house was Lord Ram born
Ram Siya Ram Siya Ram A jai jai Ram
In the third verse we learn why the Lord comes to be incarnated as an avatar in human form. Rama is an avatar of Vishnu, the preserver and sustainer. Without Lord Vishnu the world would fall apart all virtue order and reason, everything that stabilizes the mind and world opposing the darkness and chaos, light and love, this is Lord Vishnu. Rama, Jesus, Buddha, any world savior comes as a physical representation of Lord Vishnu, when the mind and the world are in crisis. All the countless heroes from myth, history, etc. like Odysseus, Daniel Boon, Nobunaga, Ann Frank, so on and so worth are all embodiments of Vishnu to some extent. These heroes all had something which embodied the light that they came to save which represents Dharma or the morally upright path. Some heroes are purer than others, Rama, Jesus, Mary, Buddha, Mother Theresa are among the purest, without selfish interests that come from darkness and ignorance.
How do we know that the mind and the world is in crisis? There is disease in various different forms; in the mind this can take the form of anxiety etc.; in the world it might take the form of desecrating holy sanctuaries or rituals, murder, vandalism, etc. When these misdeeds go unpunished for so long a universal cry to the Lord goes our from those that are devoted to dharma are unable to practice this is when the merciful Lord takes form in an incarnate being, an avatar. Rama, the adorable merciful Lord, slays the demons, asuras, of the mind and the world who are preventing the practice of dharma. Once dharma is once again established the mind and world can once again become peaceful and harmonious.
A devotee most be unceasingly surrendered to and ever show great love for that which one desires in order to obtain that which one desires. When the devotee's desire is placed on the Lord, they will surely achieve peace and harmony. The Divine Mother grants all desires whether spiritual or material but only if the devotee is ever meditating on Her. It is only with unceasing devotion that Lord Rama comes to be incarnated in one's heart and in the world, ever establishing bliss and love throughout all the universe.