The terror of God, i.e. a great terror sent from God, as Exodus 23:27 Joshua 2:9,11 2 Chronicles 14:14, 2 Chronicles 17:10. So we read of a sleep of God, 1 Samuel 26:12. Nothing less could have secured Jacob, considering the great number, power, and rage of his enemies.
Related Commentaries of Genesis 35:5
Genesis 35:5
5 And they journeyed: and the terror of God was upon the cities that were round about them, and they did not pursue after the sons of Jacob.