One of the reasons behind zemiros, bidavka on shabbos, is to protect from milchemes gog umagog, like on of the 3 seudos on shabbos is a segulah to be protected from milchemes gog umagog.
The zemira part is the shira to Hashem, kineged the cursing and apikorsus of gog and magog, and Shabbos is one of the 3 osos, that gog and magog come against, ayin the chassidishe sefarim.
As torah learning is also called shira, Torah learning on Shabbos is also extremely important for this inyan.