He was nervous, because, as I implied, he had previously deceived and betrayed his twin brother Esau, and Esau had tried to kill him. Many years have now passed, but Jacob didn't know if Esau had forgiven him. He suspected the bitterness still lingered, and as journeyed back home, he sent messengers to find out. In great fear and distress Jacob divided the people who were with him into two groups, and the flocks and herds and camels as well. Then Jacob, who had never been a religious man, decided he had better pray about things.
Some people only pray when they are in trouble, and that seems to have been Jacob's pattern.
Notice how he addressed God. O God of my father Abraham, God of my father Isaac, O Lord, who said to me, 'Go back to your country and your relatives, and I will make you prosper,' I am unworthy of all the kindness and faithfulness you have shown your servant. I had only my staff when I crossed this Jordan, but now I have become two groups. Save me, I pray, from the hand of my brother Esau, for I am afraid he will come and attack me, and also the mothers with their children. Jacob proceeded to make some preparations as nightfall stole over the desert.