Yehoshua 22:5

But be shomer to do the mitzvah and the torah, which Moshe Eved HASHEM charged you, to love HASHEM Eloheichem, and to walk in all the darkhei HASHEM, and to be shomer mitzvot regarding His commandments, and to have deveykus (attachment, cleavimg to G-d) to Him, and to serve Him in avodas [kodesh] with kol levavchem uvkhol nafshechem (all your heart, with all your nefesh).