Sforno on Exodus 20:1/ספורנו על שמות כ׳:א׳

1וידבר אלוקים, after Moses had completed warning the people G’d proceeded to utter all these commandments, as we know from the testimony of Moses in Deuteronomy 5,18 את כל הדברים האלה דבר ה' אל כל קהלכם בהר, “all these words the Lord spoke to your assembled ranks from the Mountain.”