Sir, I understand this not to be true.
1 Peter 1:19-20
"But with the precious blood of Christ, as of a lamb without blemish and without spot:
Who verily was foreordained before the foundation of the world, but was manifest in these last times for you,"
He wasn't literally slain "before the foundation of the world."
He was "foreordained" before the foundation of the world to be literally slain.
This is predestination! God's foreknowledge that man would sin before He created man, and the predestination was His plan of Redemption to redeem man from his sin.
"Whosoever will let him come", is who will be elected for this plan.
You see, there are 2 types of Election in the Scripture. Israel is the Elect of God even though they are not saved as a nation.
And there is the general Election, the "whosoever will" that choose to come at the call.
God through His foreknowledge knew every single person who would accept that call, they are the Election from the foundation of the world, already known to Him in the very beginning.