Shavua Tov. When Yosef told his father and brothers, his second dream, the Torah tells us that the brothers hated him for this. But his father שמר את הדבר.
Rashi translates the word שמר to mean that he anticipated the matter. Yakov wasn’t so sure that Yosef’s dreams were meaningless and the words of an arrogant young man. He thought he would wait and see how things played out.
There are Rabbis who felt that there is a reason why we say זכור ושמור in connection with Shabbat. זכור is to remember Shabbat and we do this by making Kiddush Friday night. But perhaps שמור doesn’t really mean observe Shabbat but “anticipate” Shabbat’s coming. We have a precedent that Yakov meant שמר to mean anticipate.
How do we anticipate Shabbat? We do this already by Friday afternoon. We can Daven Mincha Gedola and have our Shabbat preparations completed early, in anticipation of Shabbat. The siren announcing Shabbat in Jerusalem is meant to mean that Shabbat has begun; it is not an announcement to now jump in the shower!
We must anticipate Shabbat in order to observe שמירת השבת.