"Bind Up the Testimony" (Isaiah 8) March 21
Chapters 7-12 is a major section of Isaiah containing "a series of prophecies related specifically to the Syro-Ephraimite wars—the invasion of Judah by Rezin and Pekah. These prophecies aimed to call Judah back to faith in God" (Nelson Study Bible, note on 7:1-12:6). Of course, these prophecies have a much broader application than this, but they were given in this time frame and no doubt carried some significance for those who heard them. That the prophecy of this chapter is tied to the previous one is most easily discernable from the reference to Immanuel (8:8; compare 7:14). The name means "God With Us," a phrase repeated in verse 10 as a warning of destruction to all the enemies of God's people, including Assyria.
Verses 13-15 discuss how Isaiah (and those trying to follow in his steps) was to trust in God who would be his help, but that God would be a stumbling block to Israel and Judah. The apostle Peter later discusses the same subject, and he quotes from this passage in making his point, applying it to Jesus Christ, who was God in the flesh (1 Peter 2:7-8). Combined with Isaiah 28:16, verse 14 also finds its way into Paul's writings (Romans 9:33).
We then see the words: "Bind up the testimony, seal the law among my disciples" (Isaiah 8:16). This may refer back to verse 1, where Isaiah was told to write the prophecy on a scroll. Perhaps Isaiah's followers were to protect and preserve his words. Yet in verse 20 we see the statement: "To the law and to the testimony! If they do not speak according to this word, it is because there is no light in them." Here "the law" is generally understood to refer to the first five books of the Bible, while "the testimony" refers to all Scripture beyond them. "This word," then, is the Word of God. If people want to seek God, they must search His Word and heed those who faithfully teach and live by that Word. Instead, people were looking to paganism and the occult for answers—just as they do today—which was clearly a violation of the law and the testimony (verses 19-20).
Isaiah's book is indeed part of the testimony constituting Holy Scripture. Yet it may be that this prophecy was intended to imply far more than the inclusion of his book. In fact, it would seem to imply the completed written revelation of God, laying down the full requirements of His laws. Perhaps it is God speaking in verse 16, saying His disciples would seal or complete His revelation to mankind. In that case, this would appear to be referring to God's written revelation being finished by the disciples of Jesus Christ in the New Testament. This seems quite reasonable considering the other prophecies of Christ in immediate proximity.
Verses 17-18, explaining how Isaiah and his children are signs to Israel, are quoted in part in the book of Hebrews (2:13).