Then shook (esaleusen tote). Old verb as in Matthew 11:7 . He hath promised (ephggeltai). Perfect middle indicative of epaggellw and it still holds. He quotes Haggai 2:6 . Will I make to tremble (seisw). Old and strong verb (here future active) seiw, to agitate, to cause to tremble as in Matthew 21:10 . The author applies this "yet once more" (eti apax) and the reference to heaven (ton ouranon) to the second and final "shaking" at the Second Coming of Jesus Christ for judgement ( Matthew 9:28 ).