Our Mishna on Amud Beis teaches that any situation where there is a shofar blast sounded on the eve of Shabbos or a Festival to stop the people from performing labor and to demarcate between the sacred and the profane, there is no havdalah recited at the conclusion of the Shabbos or Festival in prayer and over a cup of wine. And any situation where there is havdalah recited, there is no shofar blast sounded.

That is to say, when entering a stricter, holier status, there is a shofar blast to alert everyone to abide by the new requirements, such as from weekday to Shabbos, weekday to Yom Tov and Yom Tov to Shabbos. There is no havdalah, even from Yom Tov to Shabbos, since it is an increase in holiness and prohibition of work.

However, from Shabbos to Yom Tov, or Shabbos to weekday or Yom Tov to weekday, there is havdalah, but no shofar. This is because the level of holiness and restriction is being reduced.

Mei Hashiloach on Chulin (ibid) offers a metaphoric interpretation for this phrase. The shofar blast represents a cry and prayer to God (as on Rosh Hashanah and fast days), and in this sense it represents a request that God accept all the actions of the week as globally positive, without discrimination or discernment. That is the Shofar without the havdalah, which shares the same Hebrew root as to discern.

Shabbos is a process of taking a step back and allowing Hashem to make everything complete. We cannot do more at this time except ask that He accept and fix it all, just as the Shofar does for our sins.

The Gemara Shabbos (118a) states:

“Rabbi Yoḥanan said in the name of Rabbi Yosei: With regard to anyone who delights in the Shabbos, God gives him a boundless portion. As it is stated: ‘If you keep your feet from violating Shabbos, from pursuing your affairs on My holy day, and you call Shabbos a delight, the Lord’s holy day honored, and you honor it by not going your own way, or attending to your own matters or speaking idle words. Then you shall delight in the Lord…’”

This boundless portion is the power of Shabbos to complete our efforts and make them whole in a way that we cannot. This power is channeled as we bring the holiness in, and honor the Shabbos and refrain mentally and physically from our mundane worries. If we do our part, so to speak, it makes room for God to do the rest.

Yet on Motzai Shabbos, at the beginning of the week, it is a time for havdalah and no Shofar. That is to carefully discern and plan the week’s activities so that they are meaningful and moral. No need to pray for acceptance; instead, focus on choosing what is acceptable.