The Ramayana is acclaimed for the Charama Sloka wherein Lord Rama vows to protect anyone who seeks succour at His feet. It is a promise that continues to give mental strength to countless Jivatmas struggling through the cycle of Samsara.
According to the Vaishnava tradition, the act of surrender (Saranagati) comprises six aspects — abiding by the ethical path of the scriptures and avoiding those acts that are not sanctioned in them, absolute faith in the Lord's protection, understanding one's inability to protect oneself and feeling absolutely dependent on Him and His mercy, total involvement with the Lord, and above all renouncing the sense of I and Mine in toto.
The principle of Saranagati as the most effective means for salvation is exemplified in the context of Vibhishana's surrender, said Srimati Jaya Srinivasan in a discourse. All the six requirements are fulfilled in his case and the Lord is also willing to accept his plea for refuge.
Ironically, Vibhishana sought Rama's succour at a time when the latter was actually planning strategies to attack Ravana. The omniscient Lord knew the sincere and true heart of Vibhishana and had decided to take him in His fold; yet he wanted to elicit some kind of a consensus and sought the opinions of Sugriva and Jambhavan.
Sugriva and others could read the situation from what appeared to be the most rational viewpoint, that is, downright suspicion. But Vibhishana had abandoned his brothers, kingdom, etc., and had no other option but to offer his self to Rama, the Supreme Being incarnate.
Hanuman's lone voice echoed Rama's decision to accept Vibhishana's surrender unconditionally. Hanuman recalled his meeting Vibhishana in Ravana's court and certified to his inherent Dharmic nature as opposed to Ravana's demonic tendencies.
Hanuman drew attention to Vibhishana's transparency and straightforwardness that made clear his inner thoughts. Vibhishana tried to dissuade Ravana from his evil ways and also advised him in the matter of treating the messenger Hanuman.