Excellent find.
The opening is a setup to rationalize and justify the upstart envier Mohamed the Prophet (that's what he was when he started out), by conflating Biblical teachings with Mo's autobiographical account of how "everybody was against him", conveniently leaving out how "everybody" was converted to non envious believers, the point of the sword.
Your right, that sentence marks a 180 degree turn in the message of the sermon.
Louis Farrakhan clearly stands on the bible and all those who have studied it, and those that translated the writings into English for him. Either Islam doesn't stand as tall, or plagiarizing Arabic text is too much work.