Parashat Yitro is when the giving of the Torah happens. During this magnificient event, the 10 Commandments were given. The fourth of these commandments is to remember the Shabbat, as it is stated:

זָכ֛וֹר֩ אֶת־י֥֨וֹם הַשַּׁבָּ֖֜ת לְקַדְּשֽׁ֗וֹ

Remember the sabbath day and keep it holy. (Exodus 20:8)

Zachor(remember) it’s a similar word to zachar(masculine). The Zohar explains that the secret of the masculine quality is taking the parts from the upper worlds. This is accomplished through the preparation for Shabbat during the weekdays. By having in mind the Shabbat during the week is how the Shabbat comes to be holy, comes to be remembered. 

The Zohar says that there is a higher covenant between Hashem and the Jewish people where there is no place for forgetfulness. There are Angels that are in charge to remind the positive and negative things a person do. When a person keeps Shabbat, it provoques as if Hashem would forget about the wrong doing the person did. It also goes the other way around, if the person do not keep Shabbat accordingly, Hashem, as if, forgets...