Thayer's Greek Lexicon

 1. to fall upon, to rush or press upon
  1) to lie upon one
  2) to fall into one's embrace
  3) to fall back upon
2. metaph.
  1) to fall upon one i.e. to seize, take possession of him
2a1. of the Holy Spirit, in his inspiration and impulse
2a2. of reproaches cast upon one