"For almost the entirety of its ancient existence, Israel/Judah was politically and militarily insignificant. Although it enjoyed some periods of relative strength and security, it was dwarfed by the wolves that surrounded it.  At various times, the Egyptians, Assyrians, Babylonians, Persians, Greeks and Romans were some of the imperial powers that extended their dominion over minor states within their grasp, including Israel/Judah. Subjugation and assimilation was a ceaseless threat.  It is within this political context that the Bible presents the notion of salvation. That is, biblical 'salvation' means salvation from empire."
--Craig Evan Anderson

http://biblestudyandthechristianlife.com/saved-from-what/
(Excellent Q&A in the Comments section also)