Always ‘WATCH OUT’ for the ATTACK from the ENEMY: “My heart wavered, fearfulness frightened me; the night for which I longed He turned into fear for me. Prepare the table, set a watchman in the tower, eat and drink. Arise, you princes, anoint the shield! For thus has the Lord said to me: ‘Go, set a watchman, let him declare what he sees.’” (Isaiah 21:4-6)
The prophecy by Isaiah was made about 200 years before the fall of Babylon when he prophesied that Babylon would be conquered by Elam (Persia) and Media (v. 2). Babylon was a flat country, which was abundantly watered and vulnerable to the attack from the enemy forces. In this vision that gives the background of the above passage, Isaiah sees the events in which he is transported into the future to observe the Media-Persian invasion of Babylon. Thus, he predicts the fall of the very nation that would conquer and deport his own nation Judah eventually!
When God showed Isaiah this vision during the night, it was so terrible that it caused great anguish to Isaiah. The horror and destruction that was to befall the Babylonians during that night of feasting and drunkenness was beyond any words could describe adequately. Although Isaiah longed for the fall of Babylon, he feared its consequences to Judah as now no one could rescue Judah from Assyria. Isaiah had hoped that Babylon would stop the advances of Assyria and thus save the Jews from suffering!
In the above passage, Isaiah imagines himself among the exiles in Babylon and cannot help feeling moved by the calamities which come on it. The prophet supposes himself one of the banqueters at Belshazzar's feast, on the night that Babylon was about to be taken by surprise; hence his expression, "the night for which I longed" (see v. 4; Isaiah 14:11; Jer. 51:39). This night that Isaiah mentions may be in reference to King Belshazzar’s grand banquet that is described in detail in Daniel 5:1-31.
In his vision, Isaiah first summons the feast in Babylon to be prepared by furnishing it with meats and drinks. The Babylonians would be feasting when their enemy was at their doors. Having summoned the princes of Babylon to eat and drink, Isaiah summoned them again to anoint the shield in preparation for self-defense. Babylon had many watchtowers on its walls to give notice of any approaching danger while the party was going on. God's direction to Isaiah was to "declare" what he saw just like a watchman (v. 10).
However, "that very night Belshazzar, king of the Chaldeans, was slain, and Darius the Mede received the kingdom" (Dan. 5:30-31). In one night, the self-sufficient Babylon fell to her invaders in 539 B.C. Thus, the Apostle John repeats Isaiah’s solemn statement (v. 9) in the book of Revelation (18:2) with a double emphasis: “Babylon is fallen, is fallen!” After the invasion the city of Babylon was indeed “fallen” with all her idols demolished!
The destruction of Babylon prophesied by Isaiah gives us a glimpse of how the enemy attacks us personally, even today. We have a real enemy – Satan – who is always looking to attack us, so we should "be sober, be vigilant; because our adversary the devil walks about like a roaring lion, seeking whom he may devour" (1 Pet. 5:8). We need to "resist him (Satan), steadfast in the faith" (1 Pet. 5:9) by "fighting the good fight of faith" (1 Tim 6:12). The way to do that is to "resist the devil and he will flee from us" (James 4:7). We should "put on the whole armor of God that we may be able to stand against the wiles of the devil" (Eph. 6:11).