הלכה על פסחים 211:5

That is that He commanded us to sanctify the Shabbat and to say things at its beginning and its culmination. In them, we mention the exodus from Egypt, the holiness of the day and its elevation and distinction from other days that precede it and follow it. And that is His, may He be blessed, saying, "Remember the Shabbat day, to sanctify it" (Exodus 20:8) - meaning to say, mention it and sanctify it with a blessing. And in explanation they said (Pesachim 106a), "Mention it over wine at its beginning and its culmination" - meaning, Havdalah, which is also part of mentioning the Shabbat and the arrangement of its commandments. And the regulations of this commandment have already been explained at the end of Pesachim and in other places. (See Parashat Yitro; Mishneh Torah, Shabbat 29.)