ויירא יעקב מאד (upon hearing this) “Yaakov was very much afraid;” you may well ask that after Yaakov had been met by angels, as we read at the end of the last portion, and these angels were clearly meant to protect him, what did he have to worry about? This obvious question is answered by our sages by explaining that one of these angels was Michael, Yaakov’s protective angel, whereas the second one was Samael, Esau’s angel. Knowing this, Yaakov had no way of knowing which of these two angels was more powerful.
Chizkuni on Genesis 32:8
There is a fascinating interpretation in the rabbinical texts that suggest that the messengers involved aren’t merely angels, but are two specific angels:
Michael – the guardian angel of Jacob, and Samael – the guardian angel of Esau.