John Calvin Commentary Genesis 4:16

"And Cain went out from the presence of Jehovah, and dwelt in the land of Nod, on the east of Eden." — Genesis 4:16 (ASV)

And Cain went out from the presence of the Lord. Cain is said to have departed from God's presence. This is because, while he had until now lived on the earth as in a dwelling belonging to God, he now wanders like an exile, removed far from God’s sight and beyond the limits of His protection.

Alternatively, (which is not less probable,) Moses represents him as having stood at the bar of judgment until he was condemned: but now, when God ceased to speak with him, being freed from the awareness of His presence, he hurries elsewhere and seeks a new dwelling, where he may escape God's sight.

The land of Nod undoubtedly obtained its name from its inhabitant. From its location on the eastern side of Paradise, we may infer the truth of what was previously stated: that a certain place, distinguished by its pleasantness and rich abundance of fruit, had been given to Adam as a dwelling. For, necessarily, that place must be limited, which has opposite aspects towards the various regions of the world.