Rashi on Exodus 19:3/רש"י על שמות י״ט:ג׳

1ומשה עלה AND MOSES WENT UP on the second day of the month (Mekhilta); for all his ascents to the mountain were made early in the morning, as it is stated (Exodus 34:4) “And Moses rose up early in the morning [and went up unto mount Sinai]” (Shabbat 86b).

2כה תאמר THUS SHALT THOU SAY — Thus, i. e. in this (the Hebrew) language (cf. Mekhilta) and in this form of words.

3לבית יעקב TO THE HOUSE OF JACOB — This denotes the women — to them you shall speak in gentle language (Mekhilta).

4ותגיד לבני ישראל AND TELL THE CHILDREN (lit., the sons) OF ISRAEL — explain to the men the punishments and the details of the commandments in words that are as hard (distasteful) as wormwood (גידין) (cf. Shabbat 87a; Midrash לקח טוב‎).