Yesod represents the area of Shmiras Habris, so today is a very auspicious day for progress in these areas.
The week of Yesod in the Sefirat HaOmer corresponds to the rectification of the holy bris. Shabbos is Malchus She'biyesod. "Malchus" is the all-inclusive day, which is the highlight and culmination of the week of "Yesod".
Each day of the counting, we are called upon to rectify another sefirah. This is an integral part of the process of inner purification that we are to undergo as we approach the holiday of Shavuos. We are not only to mention the day, but also to undertake the detailed, laborious toil of perfecting our character traits and the channels of celestial blessing that are directly parallel to them, just as a marionette puppet is connected to the hand above, or just like the keys of a piano are connected to the chords inside the piano's lid. Each time a key is hit, a different sound is produced. So too, each time we improve a character trait, a channel of blessing is cleansed in the spiritual worlds above, releasing a flow of blessing to our world below.
Today and this Shabbos (Malchus She'biyesod), is an especially auspicious time to take upon ourselves more stringency in purity, in preparation for the giving of the Torah!