Bereshit (Genesis) 31:20 records that Yaakov “stole” Lavan’s heart since he fled from Lavan’s house in Haran without telling Lavan that he was leaving. The following verse, 31:21, then records that in this flight Yaakov crossed the river, which is commonly understood to mean the Euphrates. Why did Yaakov not inform Lavan that he was leaving? This seems to be acting in a sneaky manner. If Yaakov had really changed his character during his stay in Lavan, then he should not have been sneaky, but should have left in an open manner. Also, why do we need to know that Yaakov crossed the Euphrates?
Afterwards, 31:22 records that after three days Lavan learned that Yaakov had fled. Lavan then chased down Yaakov and caught up to Yaakov by the hills of Gilead, 31:23. This led to the final encounter between Lavan and Yaakov, 31:26-55, which began by Lavan questioning Yaakov, why had he fled without telling him, 31:26-28.
Yaakov’s answer to Lavan was that he was worried that had he informed Lavan that he was leaving, Lavan would have stolen his wives, i.e. forced Rahel and Lea, Lavan’s daughters, to remain in Haran, 31:31. We see later on that Lavan did claim “ownership” of Yaakov’s wives, 31:43, but why was Yaakov not worried that Lavan would steal his wives on the hills of Gilead? Did Yaakov think that Lavan would not have chased him down? Or, did Yaakov think that he could get to the land of Israel before Lavan chased him down? Was Yaakov surprised by the sight of Lavan?
Seforno (on 31:31) suggests that in Haran, Lavan had many supporters, and hence he could have forced Rahel and Lea to stay in Haran, but on the hills of Gilead, Lavan did have enough men to impose his will on Yaakov. This approach seems to be based on the idea that Yaakov was not sure that G-d would physically protect him from Lavan in Haran, which I doubt. Also, most likely, Lavan had taken enough men with him on the hills of Gilead to impose his will, just that he was stopped by G-d’s intervention, 31:24, as could have happened in Haran.
My guess is that Yaakov was pretty sure that Lavan would chase him down, because the Torah records, from the perspective of the narrator, that Yaakov had stolen Lavan’s heart by running away, 31:19, and there is no reason to believe that Yaakov was unaware of this reaction. If this is true, then Yaakov could not really have hidden from Lavan. Even had he gotten to the land of Canaan, Lavan would still have tracked his down. It is even possible that Yaakov waited for Lavan on the hills of Gilead. The logic would be that Yaakov was not worried about Lavan since G-d had already assured him that He would be with him, 31:3, and for Yaakov it was better to finish with Lavan before having to deal with Esav. How then did Yaakov gain by meeting Lavan on the hills of Gilead instead of being in Haran?
My thought is that had Yaakov stayed in Haran he would have been subject to the laws of Haran, and then legally Lavan would have been able to keep Rahel and Lea in Haran. We see the importance of the local jurisdiction of Haran after Lavan switched Rahel and Lea on the marriage night, 29:23. It was clear that Yaakov had been working for Rahel, but still Lavan said the law in this place (Haran) was that Yaakov had to marry Lea first, 29:26. Even on the hills of Gilead, Lavan claimed that everything that Yaakov had, including Yaakov’s wives, really belonged to him, 31:43. Lavan was making this claim since he was applying the laws of Haran despite the fact that he was outside of Haran. Thus, Yaakov wanted to leave Haran’s jurisdiction, which is the importance of 31:21 that he passed over the Euphrates, which meant leaving Haran’s jurisdiction, and then Rahel and Lea would legally stay with their husband, Yaakov, instead of their father, Lavan.