The writer uses past tense to describe a future event. Alternate translation: "If the Lord had not decided that he would shorten those days" (See: [[rc://en/ta/man/jit/figs-pastforfuture]])
"had shortened the time." It may be helpful to specify which "days" are referred to. Alternate translation: "had reduced the days of suffering" or "had shortened the time of suffering" (See: [[rc://en/ta/man/jit/figs-explicit]])
The word "flesh" refers to people, and "saved" refers to physical salvation. Alternate translation: "no one would be saved" or "everyone would die" (See: [[rc://en/ta/man/jit/figs-synecdoche]])
The phrase "those whom he chose" means the same thing as "the elect." Together, they emphasize that God chose these people. (See: [[rc://en/ta/man/jit/figs-doublet]])