כֹּה־אָמַ֨ר יְהוָ֥ה עֹשֶׂ֛ךָ וְיֹצֶרְךָ֥ מִבֶּ֖טֶן יַעְזְרֶ֑ךָּ אַל־תִּירָא֙ עַבְדִּ֣י יַֽעֲקֹ֔ב וִישֻׁר֖וּן בָּחַ֥רְתִּי בֽוֹ׃
Also spricht der Herr, dein Schöpfer und Bildner vom Mutterleibe an, der dir beisteht: Fürchte nicht, mein Knecht Jakob, und Jeschurun, den ich erkoren.
Ibn Ezra on Isaiah
From the womb. With this expression the prophet alludes to Jacob (comp. Hos. 12:4; in my commentary thereon I shall explain it),1I. E. takes the expression womb literally, and refers it to the incident recorded Gen. 25:26, in the account of the birth of Jacob and Esau. or metaphorically to the time, when Israel was declared to be the people of the Lord.
Ibn Ezra on Isaiah
ישרון Jesurun. It is originally an adjective derived from ישר right; there is no other instance of this form.