Which of Chazal's teachings is this posuk alluding to?

(26,1) You shall not make for yourselves idols, nor shall you set up for yourselves a statue or a monument, and in your land you shall not place a figured stone on which to prostrate yourselves, for I am Hashem, your G-d. You shall keep My Sabbaths and fear My Sanctuary, I am Hashem.

The connection between these two posukim can be explained to be alluding to the teaching of Chazal in the gemara Yoma 87a that if someone says "I shall sin, and Yom Kippur will atone", Yom Kippur will not atone. And even according to Rebbi, who holds that Yom Kippur atones even for one who did not repent his sins, in this case where he is relying on Yom Kippur in order to sin, Yom Kippur will not atone.

Because besides Yom Kippur, we see that also Shabbos and the Beis Hamikdash atone for our sins. That Shabbos atones we see from the gemara in Shabbos 119b, where Chazal applied to it the posuk in Yeshayohu (6,7) "and your iniquity will be removed and your sin will be atoned for". That the Beis Hamikdash atones we see from the admonition of Yirmiyohu, who said (7,4) "Do not trust in false words, saying: The Temple of Hashem, the Temple of Hashem, the Temple of Hashem, are they", meaning that Yisrael relied on the Beis Hamikdash to protect them.

And in the gemara in Rosh Hashanah 17b, Chazal expounded the first two of the thirteen Attributes of Mercy - "Hashem, Hashem" - to mean that I am Hashem before a person sins, and I am Hashem after a person sins. From this we see that the phrase "I am Hashem" is appropriate to a person's state after he sins.

Thus our posuk is saying "You shall not make for yourselves idols…", relying on the fact that you will "keep My Sabbaths" and it will protect you, and you will "fear My Sanctuary" and it will protect you, and thus I will be "I am Hashem" after the sin. Do not do this because it will not help you.

And this is the same as the teaching in the gemara in Yoma that we brought in the beginning. As Chazal teach us: "Everything is hinted to in the Torah"!