Lord Rama is the Supreme Personality of Godhead, and His brothers, namely Bharata, Laksmana and Satrughna, are His plenary expansions. All four brothers are Viṣṇu-tattva and were never ordinary human beings. There are many unscrupulous and ignorant commentators on Ramayana who present the younger brothers of Lord Ramacandra as ordinary living entities. But here in the Srimad-Bhagavatam, the most authentic scripture on the science of Godhead, it is clearly stated that His brothers were His plenary expansions. Originally Lord Ramacandra is the incarnation of Vasudeva, Laksmana is the incarnation of Sankarsana, Bharata is the incarnation of Pradyumna, and Satrughna is the incarnation of Aniruddha, expansions of the Personality of Godhead. Laksmiji Sita is the internal potency of the Lord and is neither an ordinary woman nor the external potency incarnation of Durga. Durga is the external potency of the Lord, and she is associated with Lord Siva.
As stated in the Bhagavad-gita (4.7), the Lord appears when there are discrepancies in the discharge of factual religion. Lord Ramacandra also appeared under the same circumstances, accompanied by His brothers, who are expansions of the Lord’s internal potency, and by Laksmiji Sitadevi. Lord Ramacandra was ordered by His father, Maharaja Dasaratha, to leave home for the forest under awkward circumstances, and the Lord, as the ideal son of His father, carried out the order, even on the occasion of His being declared the King of Ayodhya. One of His younger brothers, Laksmanaji, desired to go with Him, and so also His eternal wife, Sitaji, desired to go with Him. The Lord agreed to both of them, and all together they entered the Dandakaranya Forest, to live there for fourteen years. During their stay in the forest, there was some quarrel between Ramacandra and Ravana, and the latter kidnapped the Lord’s wife, Sita. The quarrel ended in the vanquishing of the greatly powerful Ravana, along with all his kingdom and family.
Sita is Laksmiji, or the goddess of fortune, but she is never to be enjoyed by any living being. She is meant for being worshiped by the living being along with her husband, Sri Ramacandra. A materialistic man like Ravana does not understand this great truth, but on the contrary he wants to snatch Sitadevi from the custody of Rama and thus incurs great miseries. The materialists, who are after opulence and material prosperity, may take lessons from the Ramayana that the policy of exploiting the nature of the Lord without acknowledging the supremacy of the Supreme Lord is the policy of Ravana. Ravana was very advanced materially, so much so that he turned his kingdom, Lanka, into pure gold, or full material wealth. But because he did not recognize the supremacy of Lord Ramacandra and defied Him by stealing His wife, Sita, Ravana was killed, and all his opulence and power were destroyed. Lord Ramacandra is a full incarnation with six opulences in full, and He is therefore master of all opulence.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Second Canto, Chapter 7 – Text 23