הנה אנכי שולח מלאך לפניך, the angel of which the Torah speaks here is Michael, the great prince, the one of whom Gavriel said to Daniel: “at that time Michael the great prince who stands beside the sons of your people will appear.” (Daniel 12,1). It is also written in Daniel 10,21 ואין אחד מתחזק עמי על אלה כי אם מיכאל שרכם, ”No one is helping me against them except your prince Michael.” This is also the angel who said to Joshua “I am the prince of the hosts of the Lord, now I have come.” (Joshua 5,14) Our sages explained in connection with this verse that the words כי שמי בקרבו, are equivalent to G’d saying that the name of the angel mentioned in our verse is “the prince (commander in Chief) of the Lord’s hosts.” We find another reference (oblique) to this when Solomon during his inaugural prayer of the Temple he had just completed, (Kings I 8,43) said: כי שמך נקרא על הבית הזה, “for Your name is attached to this house.”

כי לא ישא לפשעכם, this is a warning by G’d for the people to be especially careful not to commit any act which is offensive to G’d, as although G’d does send this angel ahead of the people, his task is not to forgive any trespasses, something reserved for G’d personally, exclusively. The prophet Isaiah 43,25 underlines this point when he quotes G’d as saying: אנכי, אנכי, הוא מוחה פשעיך, “It is I, only I, Who wipes out your transgressions.”