כֹּה אָמַר ה’ עֹשֶׂךָ וְיֹצֶרְךָ מִבֶּטֶן יַעְזְרֶךָּ אַל תִּירָא עַבְדִּי יַעֲקֹב וִישֻׁרוּן בָּחַרְתִּי בוֹ
Thus says Hashem, Who made you and formed you from the womb, Who will help you: Fear not, Jacob My servant, and Jeshurun, whom I have chosen.
Why does G-d tells us here that He formed us from the womb? The Radak explains the metaphor: Isaiah was delivering G-d’s message to the Jews in exile, which is as constricting to the nation as a womb is to a fetus. Furthermore, shortly after a baby is born, it is brought into G-d’s covenant.