Here the word "Moses" refers to the Old Testament law. This can be stated in active form. Alternate translation: "whenever someone reads the Mosaic law" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-activepassive]])
Here the word "hearts" represents what people think, and the people being unable to understand the old covenant is spoken of as if they have a veil that covers their hearts the way a physical veil would cover their eyes. Alternate translation: "they are unable to understand what they are hearing" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])