BH: The MEM Mystery

Isaiah 9:6-7 is among the most famous passages in Scripture, but there’s some contention about who it’s really about. Is it about the coming Messiah or Hezekiah? Some anti-missionaries say it’s about Hezekiah but mainstream Christianity, among others, say it’s about Yeshua. Who’s right? And how does the Mem Mystery fit in to this debate?