tn The form לֵאמֹר (le’mor) is the Qal infinitive construct with the lamed (ל) preposition. It is used so often epexegetically that it has achieved idiomatic status—“saying” (if translated at all). But here it would make better sense to take it as a purpose infinitive. God sent him to say these words.
tn The imperfect tense with the vav (וְיַעַבְדֻנִי, véya’avduni) following the imperative is in volitive sequence, showing the purpose—“that they may serve me.” The word “serve” (עָבַד, ’avad) is a general term to include religious observance and obedience.
tn The final עַד־כֹּה (’ad-koh, “until now”) narrows the use of the perfect tense to the present perfect: “you have not listened.” That verb, however, involves more than than mere audition. It has the idea of responding to, hearkening, and in some places obeying; here “you have not complied” might catch the point of what Moses is saying, while “listen” helps to maintain the connection with other uses of the verb.
tn Or “complied” (שָׁמַעְתָּ, shama’ta).