Isaiah 40 begins with the well-known line:
Comfort, comfort my people, says your God.
In English, "comfort" seems to me like a noun, as if God is thrusting comfort toward his people or something. But they are actually plural commands:
These are piel imperatives1 --"give comfort" -- with "my people" as the object to be comforted.2
How should we identify the plural entity being commanded here?
1. Apparently. I think the form is actually ambiguous; a hypothetical qal masc. pl. imp. would be identical, but this verb only appears in the nifal and piel/pual.
2. The same holds for verse 3, an idea the KJV tradition preserved in "prepare ye the way of the LORD", but also obscured (necessarily) in most modern translations.