It helps explain why God has mercy on whom He has mercy, and that He does NOT look down the corridor of time to see who will believe in order to make their so-called free will choice.
God is the only one who has perfect free will. Which means there is no outside force, or other sovereign, who constrains God to act one way or another. If there were, that force or entity would be sovereign and God would not be God. God acts most freely in all that He does because there is no other sovereign to impede, hinder, obstruct, change, influence or thwart His choices/purposes.
On the other hand, man does have constraints, limitations and restrictions on him: his will is not free but captive, captive to the FLESH, the WORLD, and the DEVIL. Free will is a myth. Man does not have it because of these overpowering constraints, and is only free to act according to the easy sinful nature that he was born with. The flesh, the world, and the devil cause man’s will to be in TOTAL BONDAGE to all that is evil, and leaves the will captive, bound, and totally incapable of choosing the good that would set it free. These forces are so powerful and strong, causing man to be at enmity with God, and can only be overcome by God’s powerful intervention, not the weak and sinful will of man. Can a Leopard change his own spots?
So, to my main point: when God elects a person, He acts most freely according to the good pleasure of His will, and His choices are not based on anything good or bad in the individual person, or any foreseen faith the person may display in the future. God’s electing grace is solely based on His good pleasure, His love, His freedom to choose, and ultimately for the glory of His name. (There are of course other factors, as well).
If God based His choices on the actions of men, whether their actions were good, bad or the fact that He saw future faith in them, then God’s choices would not be free. His choices would be conditioned on something outside of Himself, something found in man. This destroys God’s freedom to act as He so pleases. God does not condition His free will choices on anything external to Himself. There are no constraints put on God to choose one way or another. THIS IS FREEDOM--- and only God can possess true freedom.
“For the children being not yet born, neither having done any good or evil, that the purpose of God according to election might stand, not of works, but of him that calleth (Rom 9:11).”