The book of Hebrews was certainly meant for a target audience (perhaps the messianic church). But, like all the letters of the new testament it is of educational use to the whole church. There are truths found there that are not easily seen or included in other letters. There is a covenant with the physical Israel and there is a covenant with the spiritual Israel. Each will have their fulfillment at different times. Hebrews is trying to deal with the cross over effect between the two.
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