STANZA 15

6. balm of Gilead - Gilead (during the biblical era) was a mountainous region of ancient Palestine situated east of the Jordan River, between the Sea of Galilee and the Dead Sea and was well known for its balms (ointments that sooth or heal a person). In order to appreciate the full meaning of what Poe meant in this phrase, you will need to know a bit of history surrounding the area known as Gilead.
    "At the commencement of the Christian era, Palestine was divided into three provinces, namely Judea, the most southernly; Samaria, the middle and Galilee, the most northernly - all to the west of the Jordan River."  Gilead, an unspecified area under the Galilee Region, was located east of the River Jordan and thusly fell under what was known as the Northern kingdom of Israel (the Northern Kingdom included all lands both east and west of the Jordan River whereas the region of Galilee was confined to the lands west of the Jordan River.)
    God had said, in speaking to his appointed prophet Jeremiah, that he was angry with the inhabitants of the Northern Kingdom for having forsaken him and for worshipping other God's (Jeremiah 1:16 - Old Testament.) The Northern Kingdom,, having forsaken their Lord and having gone against all his previously declared laws and having abandoned those laws of God (such as the people becoming adulterers etc.) had in turn, neglected their own people, becoming selfish, and helping only those of their own "new" faiths and religions. (Editor's Note1)
    Having forsaken God, the Lord had said to Jeremiah that he was going to punish all those in the entire Northern Kingdom for their sins against him. (Bibliography 4)