“These words Yahweh spoke to all your assembly.” This refers to God Himself speaking the Ten Commandments in a loud voice from Mount Sinai, which occurred between Moses’ third and fourth time up Mount Sinai.

[For more on God speaking the Ten Commandments directly to the Israelites, see commentary on Exodus 19:9.]

“And he wrote them on two tablets of stone.” God wrote the Ten Commandments on stone on Moses’ fifth trip up Mount Sinai.

[For more on Moses’ trips up and down Mount Sinai, see commentary on Exodus 19:3.]