This section of prophecy gives us glimpses of the future Tribulation time, as further described in Revelation. For believers, the Rapture of the Church will have already happened. Although there will be some who put their faith in Christ during this time, the earth is ripe for the judgment of God that He has withheld for so long.
“You will keep in perfect peace all who trust in You, all whose thoughts are fixed on You!” (Isaiah 26:3, NLT)
How do you reconcile God being both just and merciful?