The Book of Isaiah—especially chapters 40–55, often called Second Isaiah—is one of the most powerful affirmations of monotheism in the Hebrew Bible. In contrast to earlier periods where Israelite religion may have included elements of henotheism (recognizing many gods but worshiping only one), Isaiah presents a clear theological shift: there is only one true God, Yahweh, who alone is sovereign.
Here are key verses that demonstrate how Isaiah articulates and embodies monotheism:
Isaiah 43:10–11
“Before me no god was formed, nor shall there be any after me. I, I am the Lord, and besides me there is no savior.”
This verse outright denies the existence of any other god, past or future. God is not merely the supreme god—He is the only one.
Isaiah 44:6
“Thus says the Lord, the King of Israel and his Redeemer, the Lord of hosts: ‘I am the first and I am the last; besides me there is no god.’”
The imagery of “first and last” emphasizes God’s eternal nature and exclusivity as divine. It’s an unequivocal statement of exclusive monotheism.
Isaiah 45:5–6
“I am the Lord, and there is no other, besides me there is no god; I equip you, though you do not know me, that people may know… that there is none besides me. I am the Lord, and there is no other.”
This double emphasis (“there is no other”) is meant to erase all ambiguity. The claim is not just theological but also political and cosmic: Yahweh rules all.
Isaiah 45:18
“For thus says the Lord, who created the heavens… who formed the earth and made it… ‘I am the Lord, and there is no other.’”
Here, Yahweh is uniquely identified as the Creator—a key function that separates Him from all other so-called gods in the ancient world
Isaiah 46:9
“Remember the former things of old; for I am God, and there is no other; I am God, and there is none like me.”
God appeals to history and uniqueness—not only does He exist alone, but there is none even comparable to Him.
Summary of Themes