I love how the writer of this verse mentions Jacob's heavenly visitors so casually, as though all of us were used to having angels accompany us on our journeys! In fact, angels may be there far more often than we realize, but in this instance, Jacob is able to see them. Previously, in Genesis 28:12, Jacob had seen these angels in his dream, but now they seem to be right before him. No wonder Jacob cries out in wonder and delight, "...'This is the camp of God!' So he named that place Mahanaim." (Genesis 32:1-2 NIV) Mahanaim means "two camps" -- I suppose referring to his own group and the group of angels.
Jacob had just settled things with a somewhat hostile Laban, and now he contemplates facing his twin brother Esau after twenty years. As you may remember, Jacob had fled his homeland after deceiving their father Isaac and stealing his brother's blessing by pretending to be Esau.
Esau had always been an outdoor type of guy, but Jacob used to enjoy remaining around the tents. However, the past twenty years or so, Jacob probably spent most of his time outdoors tending Laban's flocks. This no doubt had strengthened him physically, but he probably still dreaded meeting Esau. After all, before Jacob had fled to Laban's homeland, Esau had been comforting himself by planning how he would kill him! Also, now it was not just his own life that he was responsible to protect, but also the lives of his wives and children. Jacob was probably very worried about the outcome of this reunion. God sent His angels to reassure him that this situation, too, was under His control. After all, God had told him to return to Canaan.
Of course, Jacob cannot help but make some preparations of his own, too: