What does Isaiah 21:5 mean?

The horrors to come for those in Babylon are so tragic that Isaiah is pained to his core. Great destruction is heading their way. It will be so intense that what Isaiah has seen has caused him physical agony and emotional suffering. He appears to have literally felt the terror the people of Babylon will soon experience, and it has left him devastated (Isaiah 21:3–4).

Now Isaiah contrasts that suffering with the reality of what is happening in the present moment. Scholars differ on whether the prophet is describing the scene in Babylon or in Judah. He may be saying that the Babylonians are unaware of the despair coming for them. They are going about their daily routines as if everything is normal and good. His description of eating and drinking may even suggest that they are celebrating.

An alternative is that Isaiah is referring to his own people in Judah. This would imply they are prematurely celebrating Babylon's rebellion against Assyria. They do not realize that Babylon will soon be crushed and leave them exposed to the Assyrians once more.

In either interpretation, Isaiah seems to cry out to those who aren't taking the threat seriously. He tells their leaders to take actions: to "oil the shields." The stiff, leather shields used in battle needed to be oiled regularly to keep them from becoming brittle. A brittle shield would do nothing to protect the soldier carrying it. It is also possible that oiled shields created a glare that made it more difficult for an enemy to see the action.