Rav Shimshon Raphael Hirsch says that the word zachor (in Exodus 20:7), meaning remember, is the statement telling us "to keep the Shabbos in our minds and hearts, and give verbal expression to its holiness."
Rav Hirsch is quoted as such in the Artscroll Siddur's commentary on לכה דודי (on the words, "שמור וזכור בדבור אחד") which can be found in the interlinear Artscroll Shabbos Siddur, page 71.
Does anyone know the original source where Rav Hirsch says this?