Who inspired Vibhishana to seek shelter of RAM,when he was expelled by RAWAN from LANKA?

spiritually enlightened souls attract to and respond to divine vibrations. Though Vibhishana was expelled by Ravana he never hold any grudge against him rather he took pity in him.. He firmly believed that serving Lord Ram's feet alone will lead him to his salvation. So I think the inspiration of seeking shelter of Ram is nothing but his intuition..