That's not what Paul wrote, but if we're going to make the claim that God has left his promise of possibility of our salvation up to our free will decision, then that must be what Paul meant to write.In whom also we have obtained an inheritance potentially according to the purpose of him who works all things after the counsel of our will. Ephesians 1:11
If God's promise is conditioned upon our decision, then in what sense can it be predestined? If the adoption isn't secure, then what else could predestined mean?