Treasury of Scriptural Knowledge, by R.A. Torrey, [ca. 1880]
Overview
Rev 9:1, At the sounding of the fifth angel, a star falls from heaven, to whom is given the key to the bottomless pit; Rev 9:2, He opens the pit, and there come forth locusts like scorpions; Rev 9:12, The first woe past; Rev 9:13, The sixth trumpet sounds; Rev 9:14, Four angels are let loose, that were bound.