‘That is why the children of Israel do not eat the sinew of the hip which is on the hollow of the thigh to this day, because he touched the hollow of Jacob's thigh in the sinew of the hip.'
This explanatory information was a later comment probably added when the whole was brought together, either in the time of Moses or earlier.
‘And Jacob lifted up his eyes and behold Esau came and with him four hundred men.'
The opening phrase is general. There is no necessary direct connection with a previous statement. Thus we not know how long he had to wait for the arrival of Esau. But eventually he came and with him his band of warriors. Esau has come a long way to meet his brother, seemingly out of the great love he has for his brother after twenty years of separation. But this is something Jacob cannot conceive of. He only fears his brother Esau.
Such a band of warriors would live off the land to the detriment of the inhabitants. Only the stronger groups would be safe from their depredations (compare 1 Samuel 25:15-16 which portrays what could have been the situation without David's protection). Esau's kindness to Jacob was probably not reflected in his behaviour towards others. He may well have seen this foray as a means of increasing his wealth as well as being as a welcome to Jacob.
Genesis 33:1-2 (1b-2)
‘And he divided the children to Leah, and to Rachel and to the two handmaids. And he put the handmaids and their children foremost, and Leah and her children after, and Rachel and Joseph at the back.'
Jacob now prepares his family ready for the brotherly meeting. There can be no doubting the purpose of the arrangement. If there was trouble those at the back would have a better chance of escaping. But no one would have expected Jacob to do any other apart from his preference for Rachel.