I am expanding on the answer provided by CopperKettle, well as CopperKEttle mentioned,
get to can mean allowed to
there is another way you can look at it, Let me try to explain it with a few examples
1) If you win the lucky draw, you get to go on a cruise to Hawaii
2) If you join our group, you get to enjoy the weekend in a cabin by the lake.
3) You get to eat dinner only after you finish the homework
4) You get to vote once you turn 18
In sentences 1) and 2) get to means that you have been "provided with an opportunity", in sentences 3) and 4) get to means you are "allowed to".
So in the sentence under question "All good-hearted souls get to pass through"
get to can mean
1) All good-hearted souls are allowed to (get to) pass through - in this context, you want to do something and you are given permission to do that
2) All good-hearted souls get the opportunity to (get to) pass through - in this context, you are presented with the opportunity, you can decide to take it or leave it.
So next time when you come across "get to", well you get to decide what it means.