Genesis 2:3

And the Lord blessed the Seventh Day more than all the days of the week, and sanctified it, because in it He rested from all His works which the Lord had created and had willed to make.

AND G-D BLESSED THE SEVENTH DAY AND HE SANCTIFIED IT. He blessed it through the Manna. [On all other days of the week there fell one portion per person, whereas on the sixth day — the eve of the Sabbath — a double portion fell.] And He sanctified it through the Manna [by not having it fall on the Sabbath]. And the verse is written here with reference to the future. Thus are the words of Rabbeinu Shlomo [Rashi] as quoted from Bereshith Rabbah. In the name of the Gaon Rav Saadia they have said that the blessing and sanctification refer to those who observe the Sabbath, meaning that they will be blessed and sanctified. However, from the intimation of the verse it does not appear that it refers to something which will happen in the future.
And Rabbi Abraham ibn Ezra said that the blessing signifies additional well-being, that on the seventh day there is a renewal of procreative strength in the body, and in the soul, a greater capacity in the functioning of the reasoning power. And He sanctified it by not working on it as He did on the other days. Now Ibn Ezra’s interpretation is correct to those who believe in it for this additional well-being he speaks of is not perceptible to human senses.
The truth is that the blessing on the Sabbath day is the fountain of blessings and constitutes the foundation of the world. And He sanctified it that it draw its sanctity from the Sanctuary on high. If you will understand this comment of mine you will grasp what the Rabbis have said in Bereshith Rabbah concerning the Sabbath: [“Why did He bless the Sabbath? It is] because it has no partner,”) is a direct quote from the Midrash there. (See Theodore’s ed. of Bereshith Rabbah, p. 95, variants.) In the printed edition of the Midrash, the word l’phi (because) is missing. and that which they have further related [that G-d said to the Sabbath]: “The congregation of Israel will be thy partner.” And then you will comprehend that on the Sabbath there is truly an extra soul.

ויברך אלוקים את יום השביעי , when the seventh day arrived, G’d had already created and placed in position all the needs of His creatures, including their food supply, so that it turned out that the Sabbath day was blessed with everything good. (compare author’s comment on Exodus 20,10) [I assume that this comment is based on the fact that if G’d had not created anything on that day, and especially, seeing the comment is written completely out of context, it must have referred to something which had occurred previously. Ed.]

ויברך אלוקים את יום השביעי, this refers not only to the first Sabbath but to all subsequent Sabbath days. G’d endowed every Sabbath with this blessing so that it would more readily accommodate the additional “soul” He grants Jews on that day. Job 33,30 describes this phenomenon as לאור באור החיים, “designed that he may bask in the light of life.” Our sages (Beytzah 16) state that the words שבת וינפש in Exodus 31,17 refer to the loss of this additional soul at the end of the Sabbath.

ויברך, this refers to the addition of something beneficial. The seventh day is distinguished by the fact that it enjoys additional good, i.e. additional Divine blessings. These consist of the fact that the Jew is afforded an opportunity to study Torah in a quiet unhurried setting, allowing him to derive the maximum benefit from such study. G’d extended this blessing at the time when He commanded the Jewish people to observe this day as a day of “rest” by sanctifying that day.

ויקדש אותו, the day was to be sacred in the sense that it is set apart from other days precisely because the Jewish people treat it as such. In other words, its sanctity is due to the way the Jewish people relate to it. This day constitutes a visible sign linking G’d and His people, i.e. that they, just as He, are holy through observing the Sabbath which by itself is testimony to the fact that G’d created the universe. It is a statement aimed at all of mankind announcing that the existence of the universe did not precede the existence of G’d. A researcher has stated that there is a fish in the ocean which does not swim on the Sabbath, spending the entire day resting near the beach or near a rock.
Our sages (Sanhedrin 65) describe the river Sambatyon as carrying huge stone down from the mountain every day of the week except on the Sabbath. This is why it is called Sabbatyon. They report further (Bereshit Rabbah Albeck edition pages 92-93) that the hostile Roman governor Turnusrufus asked Rabbi Akiva (in a sarcastic manner) how the Sabbath was different from the other days of the week. He answered: “what makes one warrior greater than another warrior?” Thereupon he told him that G’d had made it such. Turnusrufus enquired how Rabbi Akiva could prove this. Rabbi Akiva then told him about the strange phenomenon of the river Sambatyon resting on that day and not hurling stones down from the mountain. This simply proves that G’d, the Creator, has equipped His creatures with a sign indicating to them that the universe is the product of His creative activity, and had not preceded His existence. Our sages (Bereshit Rabbah 11,1) also explain the sequence of ויברך...ויקדש in our verse in this fashion when they say ברכו וקדשו במן, “He blessed it and sanctified it by means of the manna,” i.e. by the fact that on that day the manna did not descend from the celestial regions, seeing that G’d already provided a double portion on the previous day.