All amidah prayers—weekday, Shabbat, holiday, high holiday—consist of the same three opening and closing blessings. The middle blessings vary with the occasion.
On weekdays, there’s a thirteen-blessing-long program describing a return to life in Israel. On Shabbat and holidays, by contrast, there is one middle blessing which is related to the theme of the day.
On Shabbat, this blessing varies depending on whether you are doing the Friday evening maariv amidah, the Saturday morning shacharit amidah, the Saturday morning musaf (“additional”) amidah, or the Saturday afternoon minchah amidah.
The evening, morning, afternoon amidot treat the themes of creation, revelation, and redemption, respectively, while the musaf amidah makes reference to the additional sacrifice that used to be performed on shabbat when the temple was still standing.
The evening amidah includes vaychulu, and talks about Shabbat as the culmination of creation. The morning amidah quotes v’shamru, and makes reference to Moses receiving the Torah on Mt. Sinai. The minchah amidah waxes eloquent in describing the pure rest and equanimity that redemption will bring: “a rest reflecting Your lavish love and true faithfulness, in peace and tranquility, contentment and quietude, a perfect rest in which You delight.”
May we all be privileged to experience it soon.