Blessed Elisabeth of the Trinity has a refreshing way of thinking about predestination that elevates it and clarifies it from the prevalent Calvinistic concept.
It leads to the following analogy.
All caterpillars are predestined to become butterflies. This is their destiny–from the beginning. An individual caterpillar may not make it, but that does not change its original destiny. It was never destined to remain and die a caterpillar.
We are like that. We are all predestined for Heaven. We may not make it there, but that does not change the fact that it was our destiny from the beginning. Though some go to Hell, nobody is predestined for Hell. In addition, unlike the caterpillar, we have a say in the matter. That is why working out our salvation “in fear and trembling” is such an accurate way of putting it.
Another, more biblical, analogy would be the grain of wheat. It is not destined to remain a grain of wheat, as if holding onto that state of being is its entire goal and potential. It is predestined to become something more, but it will need to passively let go of the mode of existence that it is clinging to–as if that’s all there is and all there ever could be–and let an outside force take over to bring it to its fully developed state.
We need to do the very same thing. Precisely as Christ said, we need to let go of our clinging to our “grain-ness”, fall to the ground and die (if initially only spiritually/mystically, but which is huge nonetheless).