Ge 4:11 "So now you are cursed from the earth, which has opened its mouth to receive your brother's blood from your hand.

12 "When you till the ground, it shall no longer yield its strength to you. A fugitive and a vagabond you shall be on the earth."

This punishment of Cain is to buttress to Israel's mind the command: "Thou shall not murder."

Abel was a type of the Lord Jesus Christ. Cain was the type of the nation Israel.

Israel, later on, would murder their Great Brother, the Lord Jesus Christ. The result was God's punishment of their land and upon themselves. Israel became a barren land. And they were scattered all over the earth. They became the international squatters of the world.