Or HaChaim on Genesis 32:30/אור החיים על בראשית ל״ב:ל׳

1 הגידה נא שמך, "please tell me your name!" Although Jacob was aware that angels do not have fixed names, he asked him what this particular angel's name was at this particular time.

2למה זה תשאל לשמי, "Why do you ask after my name?" Whereas it made sense that the angel asked Jacob's name seeing he intended to change it to Israel, or at least, to inform him of that impending change. Jacob's asking the angel for his name did not have such a purpose, however. The angel therefore wanted to know the reason for Jacob's enquiry. The angel may also simply have hinted that there was no point in asking him his present name as it was apt to be changed as soon as he had accomplished his present mission. He would only have to ask him again for his name on a future occasion.