I read this quote today by Mark E. Peterson (from the 1975 Ensign talk "The Sabbath Day")
Our observance or nonobservance of the Sabbath is an unerring measure of our attitude toward the Lord personally and toward his suffering in Gethsemane, his death on the cross, and his resurrection from the dead. It is a sign of whether we are Christians in very deed, or whether our conversion is so shallow that commemoration of his atoning sacrifice means little or nothing to us.I had never really considered it before, but any given Sunday God could look down at the earth and know quickly and easily who of his children were really HIS.
Ex. 31:13 Speak thou also unto the children of Israel, saying, Verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the Lord that doth sanctify you.To "keep" the sabbath is to show the Lord that you are His. And it's amazing the kind of condensed power exists in this one day to be reminded of and recommitted to God. If we "keep" it.