Finishing the מאמר, the רבי demonstrates how the explanation of why the תנאים praised רשב"י is hinted in how they praised him as well - "שבת" and "פני האדון ה":

These are incomparably great levels, yet they connect to - and need to connect to - the lowest of levels.

This is the idea of ספירת העומר and ל"ג בעומר as well, emphasizing the connection of this holy day to this holy, G-dly person, רשב"י.