Variantly: "with all your heart": Let your heart not be "divided" over Him (i.e., do not harbor polytheistic views.)
"and with all your soul": even if He takes your soul. And thus is it written (Psalms 44:23) "For because of You we are killed the entire day. We are reckoned as sheep for the slaughter." R. Shimon ben Menassia says: Now are we killed the entire day! The reference is to (the mitzvah of) circumcision. Ben Azzai says "with all your soul": Love Him until the extraction of your soul.
R. Eliezer says: If it is written "with all your soul," why need it be written "with all your might"? And if it is written "with all your might," why need it be written "with all your soul"? For the man who holds his body dearer than his wealth, it is written "with all your soul" (i.e., though you must surrender your body); and for the man whose wealth is dearer to him than his body, it is written "with all your might" (i.e., with all your wealth).