"You shall not walk arrogantly on earth - for you cannot bore
through the earth nor can you be as tall as the mountains."
Arrogance is an outward expression of an inflated ego. A big ego is the most serious obstacle to submission to God. It is the ego inside many humans that prevents them from accepting God's omnipotence and absolute authority. Consequently, it is the ego that will undoubtedly stand between them and redemption into God's kingdom:
"Have you seen the one whose god is his own ego? Will you be his advocate?" 25:43
This is why the command to "kill your ego" is one of the first commandmants in the Quran:
"Recall that Moses said to his people, "O my people, you have wronged your souls by worshipping the calf. You must repent to your Creator. You shall kill your egos. This is better for you in the sight of your Creator." He did redeem you. He is the Redeemer, Most Merciful." 2:54