וויאמר לא אשלחך כי אם ברכתני…ויאמר לא יעקב יאמר עוד שמך כי אם ישראל כי שרית עם אלהים ועם אנשים ותוכל (וישלח לב:כז-כט)

Why did Yaakov Avinu insist that the Malach bless him and declare that his name was no longer Yaakov, but Yisroel?
The answer is that the name יעקב embodies humility—to remain lowly and modest. (עקב – “heel” – the lowest part of the body.) In contrast, the name ישראל reflects greatness, strength, and pride. As the Malach said, “כי שרית עם אלהים ועם אנשים”—“for you have striven with God and with man.”
The name change teaches a profound lesson: among Yidden, one must remain humble and lowly. But among the nations, one must hold one’s head high and maintain self-respect.
Since the Malach was the Sar of Eisav, Yaakov wanted to convey that the Yidden are greater and more worthy than the nations—they are called Yisroel, not merely Yaakov.