The firstborn of the Egyptians were slain, while the sanctity of those of the Israelites were elevated, from the same plague. As a result, we have a number of Mitzvot regarding the Bechor, the firstborn.
The Ohr Hachaim explains how the holiness of our Bechorot was elevated: Nothing can exist without some level of holiness. If the Kedusha (holiness) of a person is totally depleted, what is left is just matter that cannot live. He mentions instances where a person is left as גל של עצמות.
The Shechina כביכול appeared at midnight and was “exposed” to the firstborns.
The Egyptians had so little Kedusha left in them, and that Kedusha in them was drawn out like a magnet toward the Shechina. What was left inside the Egyptians was devoid of any holiness, and therefore expired. The Jewish Bechor, on the other hand, had enough Kedusha to instead draw the holiness into himself, thus the Jewish firstborn’s elevated Kedusha.
We are all exposed to great things and people. What we do with that exposure is up to us.
