Whose trouble is the seven-year period primarily?
The seven-year period is primarily the time of Jacob's trouble, meaning Israel's trouble. Jacob is identified as Israel, so this final seven years centers on God dealing with Israel, pouring out His wrath and vexation, with the result that a remnant of believers will come out of them. Scripture consistently shows God preserving a remnant.
Les teaches that the final seven years of human history are great and unequaled, and he identifies that period as "the time of Jacob." Jacob is Israel, so this seven-year period is primarily the time of Israel's trouble. During it, God will be dealing with Israel in His wrath and vexation. The end result is that out of them will come a remnant of believers, and Les emphasizes that all through Scripture God has had a remnant.