Cain “went out from the presence of the Lord.” God is, was, and always has been present everywhere. The Temple contained the Holy of Holies, the tabernacle did so before that. Yet, David wrote in Psalm 139 that God would be anywhere, no matter where he went.
This, then, is speaking of a couple things. It speaks of the will of God; God’s will was that Cain remain in a relationship with Him, where He had ordered things, so Cain would be protected. But, it also speaks of Cain’s heart. He’d hardened his heart so much, that he totally shut himself off from contact with God. He’d totally gone his own, rebellious way.
He didn’t have to do this, of course. As noted before, he could have repented, and accepted God’s role as Sovereign in his life. However, his mind was evil. He’d gone so far downhill, in such a short time, that he would not accept any of God’s commands. Indeed, he scoffed at the idea. He felt he could create a much better world on his own. It’s the same way the devil had tried to overthrow God; he thought he could better than God’s perfect goodness, so he sought to be as God. (Is. 14:12-14, Eze. 28:12-19)
So, Cain settled in the land of Nod. It was in the East. The whole world would fall into a pattern of man-centered religions, with many false gods. However, the East has become much better known for such religions.
Such religions are really about people. How can one better oneself on one’s own, without God’s help. That’s what Cain’s line became, for the most part – though the Bible never says there were no exceptions. However, for the most part, they were people who were focused on self.
