This parsha lists all the sacrifices starting  with the daily ones, then Shabbos, Rosh Chodesh and the holiday.  When it comes to Shabbos the Ramban says something cryptic (at least it is vague to me). Ramban notes that the “musaf” or additional sacrifice on the shabbos is different than other musafs like Rosh chodesh that includes a “chatas” or sin offering.   He says no chatas in musaf offering. Ramban says that the “congregation of israel” is like the spouse  and all is Shalom.

The SD showed this Ramban to a friend who suggested that on Shabbos the relationship of Israel and hashem is so close that a Chatas-sin offering would “ruin the mood.”  The SD think this is correct.  The whole point of offerings is to get close to Hashem-like one would in any relationship. Sometimes relationships need correction and work. Sometimes, they just need love and closeness.