Thus, the name Krsna indicates the Supreme Brahman who is the acme of these two characteristics. The yogis take pleasure in the Supreme Self which is existence, knowledge and bliss absolute. Therefore that truth, known as the Param Brahman is also called Rama. The Lord is known as Hari because he takes away the ignorance of his devotees by revealing to them the actual nature of the Supreme Lord and his personal spiritual form. Because she steals Krsna's mind, because she is the incarnation of Krsna's joy, Radha is also known by the name Hara.
Hare is the vocative form of that name.