General Information:

Jesus quotes a verse from Deuteronomy as the greatest commandment.

with all your heart, with all your soul, and with all your mind

These three phrases are used together to mean "completely" or "earnestly." Here "heart" and "soul" are metonyms for a person's inner being. (See: rc://en/ta/man/jit/figs-metonymy and rc://en/ta/man/jit/figs-doublet)