1)
What are the connotations of "asher Tzivcha Hashem Elokecha"?
1.
Rashi: With reference to the prohibition against making an image that he just mentioned, Moshe now adds 'that Hashem commanded you not to do'.
2.
Ramban (on Pasuk 20): Refer to 4:22:2:2*.
3.
Oznayim la'Torah (commentaries): With reference to the Keruvim, the Torah is now prohibiting their manufacture anywhere else other than in the Beis-Hamikdash, where Hashem commanded them to be placed. 1
1
See Oznayim la'Torah.