NOTES for Isa 26:21
"There is no wrath in Me," the Lord says today. And this is very hard to understand, because "the wrath of God" is one of the most fundamental concepts of Holy Scripture. Yet it is also one of the stumbling blocks for many. We do not want to see in our Lord the traits of the pagan Zeus the Thunderer, because this pagan god, in his other qualities, is very far from the Face of God truly revealed by Christ.
In fact, the Jewish people, like any other people, could not avoid a mythological stage in their religious development; nevertheless, they came to know a special Revelation, and these two qualities, the earthly and the heavenly, were woven together in Holy Scripture. Therefore we need to trace very carefully the whole development of the concept of God's wrath, and of wrath in general, in Scripture.
That is a separate major work, but let us recall at least this passage from the Apostle's Epistles: "Be angry, and do not sin: do not let the sun go down on your anger, and do not give the devil an opportunity." (Eph 4:25) These words are somewhat unusual and paradoxical; "be angry and do not sin," Bishop Cassian translates, making the strangeness even stronger. If the words of the Synodal Translation can still be understood as "do not sin by means of anger," that is, do not be angry at all, Bishop Cassian's rendering no longer allows such an interpretation. So we are called to be angry, but not longer than one day: "do not let the sun go down on your anger."
This can become the key to the misunderstanding described above that can arise in us today when we read the prophet Isaiah: God's wrath is real and is described many times in Holy Scripture, yet there is no wrath in Him, for it is only a healthy reaction to the "briers and thorns" brought in from outside. Therefore the sun does not go down on God's wrath. Just as it must not go down on ours.