rambam is extremely clear about bar kochba :
we know that he is not mashiach because he was killed. [rambam hilch melachim]
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and not because he transgressed katan’s psak and i quote katan here :
“… Finally, in addition to all that, the midrash notes that the final geulah is something that must come from Hashem alone, not from man’s efforts (other than Torah and mitzvos, of course).” [katan]
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so this is a clear machloket between katan and rambam
katan says final geoulah comes from HKBH alone
rambam says final geoulah can come from man’s endeavors.
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. as clear as can be .
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