Comentario sobre Deuteronómio 5:28

THAT THEY MAY DO THEM IN THE LAND. I have explained it.¹⁹⁹Above, 4:5.

ואתה פה עמד עמדי, "As for you, stand here with Me, etc." The reason for this is that seeing that up until now the Israelites had not made Moses their intermediary to accept the commandments on their behalf, G'd told Moses to stand next to Him so that He could speak to him and tell him all the commandments which he was to teach the people. Perhaps the meaning of the verse is that as far as G'd is concerned as soon as He had informed Moses of the commandments He considered the Israelites as having received these commandments. Legally, this works as follows: Supposing a woman authorises someone to accept a marriage proposal on her behalf she is considered legally marrried as soon as her delegate has received the necessary gift and documentation. The delegate's "hand" is considered as equivalent to her own. In similar fashion, once Moses, Israel's delegate, had received the commandments, Israel was committed to observe them. This is what G'd meant when He said: "and I will say them to you." He added: "you will teach them and they will carry them out."

'ואתה עמוד פה עמדי ואדברה אליך ...ועשו בארץ וגוthis is a reference to when Moses had said in 4,14 “G’d commanded me at that time to teach you to perform the commandments applicable in the Holy Land.”