Adam Clarke's Commentary on the Bible

Verse 3 (Isaiah 26:3)

In perfect peace - שלום שלום shalom , shalom , "peace, peace, "i.e., peace upon peace - all kinds of prosperity - happiness in this world and in the world to come.

Because he trusteth in thee "Because they have trusted in thee" - So the Chaldee, בטחו betacho . The Syriac and Vulgate read בטוח batachnu , "we have trusted. "Schroeder, Gram. Hebrews p. 360, explains the present reading בטוח batuach , impersonally, confisum est .

- Adam Clarke's Commentary on the Bible