Musar zu Schemot 34:30

ויראו מגשת אליו. Our sages comment on the debilitating power of sin evident from this verse. Before the sin the Jewish people were able to face the שכינה without flinching. Now, after having sinned, they were afraid to even approach Moses who, after all, was only an intermediary. We must learn from this how important it is to purify ourselves, to sanctify ourselves so that all residues of impurities due to sin are expunged. Once we have removed all traces of sin, the good we do will have its desired impact.

Our sages in Baba Batra 75a comment on Numbers 27,20: ונתתה מהודך עליו, "you will invest him with some of your glory" (when Moses is told to appoint Joshua), that Moses was to invest Joshua only with part of his glory, not all of it. The elders of that generation are reported there as having compared Moses' face to that of the sun, whereas they compared Joshua's face to that of the moon. The change in the quality of leadership of the Jewish people was felt by these elders to be a shame and an affront. Why did G–d withhold some of His goodness from the people at that time? In the Midrash Shocher Tov 21, the author elaborates on the verse in Numbers 27,20 that Joshua experienced that part of Moses' glory granted to him on the occasion of the miraculous crossing of the river Jordan. We read in Joshua 4,14: "On that day the Lord exalted Joshua in the sight of all of Israel, so that they revered him all his days as they had revered Moses." The Midrash continues that the glory of the Messiah will equal that of teacher and disciple (Moses and Joshua), since it is said of him in Psalms 21,6: הוד והדר תשוה עליו, You have endowed him with splendor and glory." This statement obviously needs clarification. Besides, since "one hundred" is part of "two hundred," how does the addition of Joshua's glory increase the glory of the Messiah?