[Note: Our Shabbat morning amidah includes a poem,
"Moshe will rejoice in the gift of his portion".]
"'Moshe will rejoice', for when our ancestors were in
Egypt and Moshe saw the weight of the slavery upon them, he requested that
Pharaoh give one day each week for them to rest. Pharaoh gave it to him, and
Moshe selected the seventh day.
"When the Jews were instructed to observe Shabbat,
Moshe rejoiced in that he had selected it. This is 'Moshe will rejoice in the
gift of his portion.'"
(Tur Orach Chaim 281 [note: the Tur continues to offer
an additional explanation)
ישמח משה כשהיו
אבותינו במצרים וראה משה כובד השיעבוד שהכבידו עליהם בקש מפרעה שיתן להם יום אחד
בשבוע שינוחו בו ונתנו לו ובחר ביום השביעי וכאשר נצטוו על יום השבת שמח משה שבחר
בו וזהו ישמח משה במתנת חלקו
Have a great day,
Mordechai