הַבִּ֙יטוּ֙ אֶל־אַבְרָהָ֣ם אֲבִיכֶ֔ם וְאֶל־שָׂרָ֖ה תְּחוֹלֶלְכֶ֑ם כִּי־אֶחָ֣ד קְרָאתִ֔יו וַאֲבָרְכֵ֖הוּ וְאַרְבֵּֽהוּ׃ (ס)
Look unto Abraham your father, And unto Sarah that bore you; For when he was but one I called him, And I blessed him, and made him many.
Read Jewish philosophical commentary on Isaiah 51:2: and classical philosophical sources.