Musar zu Schemot 19:24

Let us now return to these four groups of people who entered the פרדס. Joshua accomplished more in the פרדס than Rabbi Akiva; the Talmud in Chagigah 14 reports that the angels were about to attack Rabbi Akiva, and only G–d's intervention enabled him to re-emerge from there spiritually unharmed. Joshua, on the other hand, had been endowed with some of Moses' glory (Numbers 27,20), and Moses had demonstrated his power to prevail over the angels while he had been in the Celestial Regions and had brought down the Torah to the Jewish people from those regions in spite of the angels' objections. The elders deserted Moses on his first mission to Pharaoh (cf. Rashi on Exodus 5,1). G–d paid them back for this at the time of the revelation at Mount Sinai when they were not allowed to come close to the Mountain, as distinct from Aaron (Exodus 19,24). G–d had said to Moses: ועלית אתה ואהרון, "you and Aaron (alone) will ascend."