leich alei -- staying where you are will not work

 After Moshe begs Hashem to forgive the cheit ha'eigel, Hashem responds (33:1-3):

 לֵ֣ךְ עֲלֵ֣ה מִזֶּ֔ה אַתָּ֣ה וְהָעָ֔ם אֲשֶׁ֥ר הֶֽעֱלִ֖יתָ מֵאֶ֣רֶץ מִצְרָ֑יִם אֶל־הָאָ֗רֶץ אֲשֶׁ֣ר נִ֠שְׁבַּ֠עְתִּי לְאַבְרָהָ֨ם לְיִצְחָ֤ק וּֽלְיַעֲקֹב֙ לֵאמֹ֔ר לְזַרְעֲךָ֖ אֶתְּנֶֽנָּה

וְשָׁלַחְתִּ֥י לְפָנֶ֖יךָ מַלְאָ֑ךְ וְגֵֽרַשְׁתִּ֗י אֶת־הַֽכְּנַעֲנִי֙ הָֽאֱמֹרִ֔י וְהַֽחִתִּי֙ וְהַפְּרִזִּ֔י הַחִוִּ֖י וְהַיְבוּסִֽי׃

אֶל־אֶ֛רֶץ זָבַ֥ת חָלָ֖ב וּדְבָ֑שׁ כִּי֩ לֹ֨א אֶֽעֱלֶ֜ה בְּקִרְבְּךָ֗ כִּ֤י עַם־קְשֵׁה־עֹ֙רֶף֙ אַ֔תָּה פֶּן־אֲכֶלְךָ֖ בַּדָּֽרֶךְ

Why do we have a repetition here of the promise of Eretz Yisrael and the command to drive out the inhabitants of Canaan?  Ramban explains that Hashem was telling Klal Yisrael that although cheit ha'eigel was not completely forgiven, 1) zechus avos is still intact, hence the reference to Avraham Yitzchak, and Yaakov; 2) the promise to bring Klal Yisrael into Eretz Yisrael is still intact; 3) kedushas ha'aretz is still intact intact, and therefore the nations must be driven out שלא תשחת הארץ ולא תחנף תחת יושביה מפני חטאתם, 

The Ramban emphasizes the positive, but one could read the pasuk in the opposite way (see Tzror HaMor), as saying that because of the cheit Klal Yisrael was not really deserving of Eretz Yisrael if not for zechus avos, and (Tzror haMor does not say this part, but I think it is a logical extension) that because they were so easily led astray they need to be extra careful to drive out the idolatrous nations that were already there.

Either way, the pasuk is like a damage assessment after the cheit.  In R' Shlomo Amar's sichot on the parsha he points out that Targum Yonasan suggests something deeper:

ומליל ייי עם משה איזל איסתלק מיכא דילמא יתקף רתח רוגזי בעמא ואישיצינון בגין כן טייל אנת ועמא דאסיקתא מארעא דמצרים לארעא דקיימית לאברהם ליצחק וליעקב למימר לבנך איתנינה.

According to T.Y., the pasuk is a tikun for Hashem's anger caused by the cheit. 

Hashem was telling Moshe that were Klal Yisrael to remain where they are, Hashem was liable to grow angry at them again and there would be consequences.  

The solution is to make aliya, begin the journey to Eretz Yisrael.  That's the game changer that causes Hashem to set aside his anger.