This passage is from
Shemot 31:16-17 of Yisrael's Shabbat observance
and is related to the theme of redemption, because Yisrael will be redeemed
from exile in the merit of Shabbat observance
(Abudraham).
The verse for the pilgrimage festivals alludes to the freedom from Egypt.
This chapter of Shabbat observance
appears in the Torah immediately after the commandment to commence the
construction of the Tabernacle. This teaches that even for the sake of
building the Temple, one may not desecrate the Shabbat (Rashi) By
logical extension, this concept refutes those who may tend to relax the
observance of the Shabbat or other mitzvot for the sake of what they consider
to be noble spiritual causes.
Sources:
Artscroll Siddur
The Art of Jewish Prayer