R. Meir says: It is written: "And you shall love the L-rd your G-d with all your heart." Love him with all your heart, as did Abraham our father, as it is written (Isaiah 41:2) "Avraham, My lover," and (Nechemiah 9:8) "and You found his heart faithful before You."
"and with all your soul": as Isaac, who offered himself to be bound upon the altar.
"and with all your might (meodecha)": Confess (modeh) to Him, as did Jacob ("modeh," as in "meodecha"), as it is written (Bereshith 32:11) "I am too small for all of the lovingkindness and all of the truth that You have done with Your servant. For with my staff did I cross this Jordan, and now I have become two camps."