What did Moshe tell the people?
Targum Yonasan: He told them to come near and to accept the Torah and the Aseres ha'Dibros.
Here it says that Moshe descended. In Devarim (5:5), it says "I stood between Hashem and you"! Also, Hashem told Moshe and Aharon to ascend! And why does it not say that Moshe descended Min ha'Har to the people, like above?
Moshav Zekenim citing the Chasid: Moshe descended only half the mountain and called to the people and warned them, and he called to Aharon to ascend. Amidst this, Hashem began to say "Anochi