וַיֹּאמֶר אַל תִּשְׁלַח יָדְךָ אֶל הַנַּעַר וְאַל תַּעַשׂ לוֹ מְאוּמָה כִּי | עַתָּה יָדַעְתִּי כִּי יְרֵא אֱלֹהִים אַתָּה וְלֹא חָשַׂכְתָּ אֶת בִּנְךָ אֶת יְחִידְךָ מִמֶּנִּי translates as: And he said, "Do not stretch forth your hand to the lad, nor do the slightest thing to him, for now I know that you are a God fearing man, and you did not withhold your son, your only one, from Me.
Now what exactly is the angel saying over here "from me"? Avraham did not withhold Yitzchok from Hashem, not from the angel?