To the law and to the testimony: if they speak not according to this word, it is because there is no light in them.

ISAIAH 8:20KJV
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Isaiah 8:20 (KJV)

What does Isaiah 8:20 mean?

Isaiah 8:20 says that people should measure every message or teaching by “the law and the testimony”—God’s revealed instruction and witness. If someone’s words do not line up with this standard, Isaiah says it is because they have no true understanding or guidance (“no light in them”).

In this verse, Isaiah is speaking to the people of Judah during a time of confusion and fear, when many were tempted to seek guidance from sources other than God, such as mediums or false prophets. Isaiah insists that God’s own word—His law and testimony—is the only reliable source of truth, and anything that contradicts it should be rejected as darkness.

The Hebrew behind Isaiah 8:20

  • law (תּוֹרָה, torah): This word means instruction or teaching, often referring to God’s commands given through Moses. Here, it points to the foundational guidance God has provided.
  • testimony (תְּעוּדָה, te‘udah): This refers to the witness or evidence God has given, possibly through His prophets or the record of His actions. It emphasizes the importance of God’s revealed truth as a standard.
  • light (שַׁחַר, shachar): This word usually means dawn or morning light, symbolizing understanding, truth, or guidance. Isaiah uses it to say that those who do not speak according to God’s word lack the true light needed to guide others.

Why Isaiah 8:20 matters

  • Isaiah 8:20 clarifies that not every spiritual-sounding message is trustworthy; only those that agree with God’s revealed word are reliable.
  • The verse highlights the danger of turning to other sources for guidance, a temptation the people of Judah faced in their crisis.
  • This verse connects to the wider passage by showing Isaiah’s strong warning against superstition and false prophecy, urging the people to hold fast to what God has already made known.

Where else these words appear

“testimony” Hebrew H8584 · used in 3 verses

  • Ruth 4:7 Now this was the manner in former time in Israel concerning redeeming and concerning changing, for to confirm all things; a man plucked off his shoe, and gave it to his neighbour: and this was a testimony in Israel.
  • Isaiah 8:16 Bind up the testimony, seal the law among my disciples.

“light” Hebrew H7837 · used in 24 verses

  • Genesis 19:15 And when the morning arose, then the angels hastened Lot, saying, Arise, take thy wife, and thy two daughters, which are here; lest thou be consumed in the iniquity of the city.
  • Job 3:9 Let the stars of the twilight thereof be dark; let it look for light, but have none; neither let it see the dawning of the day:
  • Isaiah 14:12 How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!