Contradiction with Isaiah 7:14
Isaiah 7:14 follows directly after Isaiah 7:13, offering a prophetic sign, which can be seen as different in tone and purpose rather than directly contradicting.
Isaiah 7:14: Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel. [shall call: or, thou, O virgin, shalt call]
Contradiction with Isaiah 55:9
This verse speaks of God's ways and thoughts being higher than human ways, contrasting with Isaiah 7:13, where the focus is on a specific sign to Ahaz, possibly implying human limitation in understanding divine purposes.
Isaiah 55:9: For [as] the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts.