Sforno on Deuteronomy 33:5/ספורנו על דברים ל״ג:ה׳

1ויהי בישורון מלך, since that occasion G’d became “King” in Israel among all those who study Torah more than superficially.

2בהתאסף ראשי עם, at the time of the giving of the Torah, when, according to Deut. 5,19, all the elders and leaders of the people are described as approaching Moses, telling him (verse 20) that G’d had shown them His glory,

3יחד שבטי ישראל, G’d had thus become King over all the tribes of Israel at one and the same time as they all accepted His status as being their supreme authority. The words which the people used to express this acceptance were:ואת תדבר אלינו את כל אשר ידבר ה' אלוקינו אליך ושמענו ועשינו, “and you say to us all that the Lord our G’d will say to you, and we will hear it and do it.” (Deut.5,24)