Rashi (to 33:3) writes that Yaakov feared that Esav is coming to fight. Why did he think so (even after he sent a big gift)?
Seforno: He saw the fact that he was coming with the 400 men 1 as a sign that his gift had not softened his brother's heart.
Malbim: He understood that the spiritual battle he had with the angel was a preparation for a war with Esav himself. Since the angel harmed his thigh, perhaps Esav will overpower his children now. Therefore, he split them.
Army officers, to boot (according to Targum Yonasan). Refer to 33:15:151:1.
Why does the Torah mention Leah before Rachel?
Oznayim la'Torah: In time of danger, when the father is not there, the children belong with their mother - and that Torah mentions Leah first because she had the most children.
Why did Yaakov split his children now?
Malbim: Since the angel harmed his thigh, he thought that perhaps Esav will overpower his children now.
Ha'amek Davar: This was unlike yesterday, when he split his camp amidst fear lest Esav overpower. From the fight with the angel, he was sure that Esav cannot destroy anything. However, he saw that it is good to humble himself before him, lest he make a minor blow, like the angel harmed his thigh.
