the salvation of your souls

Here the word "souls" refers to the whole person. The abstract noun "salvation" can be translated with a verb. Alternate translation: "your salvation" or "God saving you" (See: rc://en/ta/man/translate/figs-synecdoche and rc://en/ta/man/translate/figs-abstractnouns)

salvation

This words presents the idea as if it were an object. In reality, "salvation" refers to the action of God saving us, or to what happens as a result.