The reason for this can be understood by the interpretation of the Kedushas Levi on the passuk גם אלה תשכחנה ואנכי לא אשכחך ( Yeshaya 49,15) that Hashem will forget the sin of the worshipping the Golden Calf which is described as “aileh” but He would not forget that Am Yisrael said naaseh venishma and received the Aseres Hadibros which begin with the word “anochee”.

The Kedushas Levi explains the Chazal as follows. Some might claim that the reason Yisrael received the Torah unquestionably was because they were deeply affected by the spiritual merit of their Avos that was a carried inheritance within themselves at that present time. To this Hashem responds then how can one explain that soon afterwards they worshiped the Aigel? Does this also stem from the spiritual inheritance of the Avos? Obviously this attests to the fact that Yisrael on their own responded naaseh vinishma just like on their own they worshipped the Aigel. This is what Hashem means when He says that I will forget the Aigel but when it comes to the merit of Matan Torah, naaseh venishma, Anochi Hashem Elokecha, I will not forget the chait of the Aigel. For by doing so I will increase Yisrael’s merit of their commitment of naaseh venishma which was said at Anochi.