They haven't been given these rights for (all) eternity - they should justify having them just like most other people have to.这些权利并非永久性地赋予他们——他们应该像其他大多数人必须要做的那样,证明自己有资格享有这些权利。
Religions gain some of their worldly power by claiming they have the key to eternity (= a state of existence outside normal life).宗教所拥有的世俗权力中有一些是靠宣称自己拥有通往永恒的钥匙获得的。