Isaiah 8:18; Isaiah 20:3

Isaiah 8:18

18 Behold, I and the children whom the LORD hath given me are for signs and for wonders in Israel from the LORD of hosts, which dwelleth in mount Zion.

Isaiah 20:3

3 And the LORD said, Like as my servant Isaiah hath walked naked and barefoot three years for a sign and wonder upon Egypt and upon Ethiopia;