The idiom "with all ... heart" means "completely" and "with all ... soul" means "with all ... being." See how you translated these two phrases in [Deuteronomy 4:29](../../deu/04/29.md). (See: [[rc://en/ta/man/translate/figs-idiom]])
Here "great" and "first" mean the same thing. They emphasize that this is the most important commandment. (See: [[rc://en/ta/man/translate/figs-doublet]])