The Alter Rebbe says in this maamar, that people who work all week long think that they are not able to connect to Hashem in prayer as deeply as the scholars who learn Torah all week. He says that this is a complete mistake. In fact, they can pray and connect to Hashem even deeper than them! This is because the greatest Light comes out from a place of darkness. Because they are involved in the darkness of this world throughout the week, when it comes Shabbos and their mind and heart to only focus on Hashem, they transform that darkness into a more powerful light than the light of the scholar who experiences Light the entire week. Because of this, the average working person has a tremendous ability to connect to Hashem during prayer on Shabbos.
