Exodus 19:3

"And Moshe went up" - On the second day. And all of his goings up were at daybreak as it is written (Exodus 34: 4) "Moshe arose in the morning."

"Thus shall you say" According to these words and in this order (Bavli Shabbat 86b).

"To the house of Jacob" - These are the women, you shall speak to them in soft speech.

"And speak to the children of Israel" - He explained the punishments and minutiae to the males, and difficult matters such [the laws of] sinews (Mekhilta).

And Mosheh on the second day went up to the summit of the mount; and the Lord called to him from the mount, saying, This shalt thou speak to the [women] of the house of Jakob, and instruct the house of Israel.

AND MOSES WENT UP UNTO G-D. From the day they arrived at Mount Sinai, the cloud covered the mountain and the Glory of G-d was there. It is with reference to this that Scripture says, And the Glory of the Eternal abode upon Mount Sinai, and the cloud covered it six days, i.e., before the Giving of the Torah. It is for this reason that Scripture says here, And Moses went up unto G-d, meaning that he went up to the edge of the mountain to be ready for Him, but he did not penetrate the thick darkness where G-d was., 20:18. And the Eternal called unto him from the top of the mountain, saying: Thus shalt thou say to the house of Jacob.
And Rabbi Abraham ibn Ezra wrote that the expression, and He called unto him, is an antecedent, meaning that He had called him [to come up to the mountain] and he went up to Him. But this does not appear to me to be correct, for the calling [mentioned in Scripture after Moses ascended the mountain] was: Thus shalt thou say to the house of Jacob. Now Ibn Ezra explains the verse to mean as follows: “And the Eternal called unto him to say, which is generally taken to mean “saying,” as meaning “to say.” The sense of the verse is thus: And Moses went up to G-d, for He had called him out of the mountain to tell him, “Thus shalt thou say to the house of Jacob, etc.” to him, Thus shalt thou say to the house of Jacob.” But this is not correct.
The meaning of the expression, he went up unto G-d, and the Eternal called unto him, is that Moses went up towards the Glory of G-d, which was abiding on the mountain to declare the Ten Commandments to Israel, and with His Great Name [the Tetragrammaton] He would speak with Moses, as is the meaning of the verse, If there be a prophet among you, etc. (Verses 6-8). See also Ramban in this chapter, further, Verse 20.