Possible meanings are 1) "no Christian who has the Spirit of God in him can say" or 2) "no one who is prophesying by the power of the Spirit of God can say."
# Jesus is accursed
"God will punish Jesus" or "God will make Jesus suffer"
This double negative emphasizes that "by the Holy Spirit" is what makes it possible for one to say, "Jesus is Lord." Alternate translation: "One can say, 'Jesus is Lord,' only by the Holy Spirit" (See: [[rc://en/ta/man/jit/figs-doublenegatives]])