Advent is a season of waiting, waiting for God to fulfill His promises. We know that most of His promises from the Old Testament were fulfilled magnificently by Jesus, but as St. Paul reminds, we have received but the first fruits of His work in our soul (cf Rom 8:23). The created world and our physical bodies still await the full implications of what He has done. We still await a new Heaven and a new earth where the justice of God will reside (cf 2 Peter 3:13). We still wait for that time when God will renew and restore all things in Christ and will vanquish Satan and his followers so that they can no longer cause harm.
There are times—times like these—when many may be discouraged. There are times when evil may seem to triumph and the victory of Christ seems far off. For indeed, we live in a fallen world, governed by a fallen angel, and we have fallen natures.
As Advent progresses, however, there comes a word of encouragement from Isaiah, who is the main prophet of reference during this season. Addressed to the fainthearted, it is an unambiguous declaration that God is working His purposes out and that nothing in this world can prevent His plan from being fulfilled.