Below is Isaiah Chapter 26 with line-by-line companion text incorporated.
His Judgments
1 In that day, this song will be sung in the land of Judah: We have a strong city; God makes salvation its walls and ramparts.
“That day” seems to mean when the New Testament Babylon shall be level with the ground. The unchangeable promise and covenant of the Lord are the walls of the church of God.
2 Open the gates that the righteous nation may enter, the nation that keeps faith.
The gates of this city shall be open. Let sinners then be encouraged to join to the Lord.
3 You will keep in perfect peace those whose minds are steadfast because they trust in you.
Thou wilt keep him in peace; in perfect peace, inward peace, outward peace, peace with God, peace of conscience, peace at all times, in all events. Trust in the Lord for that peace, that portion, which will be forever. It is our duty and will be our comfort to wait for God to keep up holy desires toward him in the darkest and most discouraging times. Trust in the Lord for that peace, that portion, which will be forever.
4 Trust in the LORD forever, for the LORD, the LORD himself, is the Rock eternal.
Whatever we trust to the world for, it will last only for a moment; but those who trust in God shall not only find in him but shall receive from him a strength that will carry them to that blessedness, which is forever. Let us then acknowledge him in all our ways and rely on him in all trials.
Jesus Urges His People to Wait Upon Him
5 He humbles those who dwell on high, he lays the lofty city low; he levels it to the ground and casts it down to the dust. 6 Feet trample it down – the feet of the oppressed, the footsteps of the poor.
The way of the just is evenness, a steady course of obedience and holy conversation.
7 The path of the righteous is level; you, the Upright One, make the way of the righteous smooth.
The pathway of life is level for those who are right with God, the righteous; Lord or Upright One, you make the way of life smooth, straight, and level for them.
8 Yes, LORD, walking in the way of your laws, we wait for you; your name and renown are the desire of our hearts.
It is our duty and will be our comfort to wait for God. To keep up holy desires toward him in the darkest and most discouraging times.
9 My soul yearns for you in the night; in the morning, my spirit longs for you. When your judgments come upon the earth, the people of the world learn righteousness.
Our troubles must never turn us from God, and in the darkest, longest night of affliction, with our souls, we must desire him; and this we must wait and pray to him for. And are to make nothing of our religion, whatever our profession may be if we do not make heart-work of it.
10 But when grace is shown to the wicked, they do not learn righteousness; even in a land of uprightness, they go on doing evil and do not regard the majesty of the LORD.
Though we come ever so early, we shall find God ready to receive us. The intention of afflictions is to teach righteousness: blessed is the man whom the Lord thus teaches.
11 LORD, your hand is lifted high, but they do not see it. Let them see your zeal for your people and be put to shame; let the fire reserved for your enemies consume them.
But sinners walk contrary to him. They will go on in their evil ways because they will not consider what a God he is and whose laws they persist in despising.
The Promise of Deliverance
12 LORD, you establish peace for us; all that we have accomplished you have done for us.
Every creature, every business, any way serviceable to our comfort, God makes to be so; he makes that work for us, which seemed to work against us.
13 LORD our God, other lords besides you have ruled over us, but your name alone do we honor.
They had been slaves of sin and Satan, but they were taught to look to be set free from all former masters by the Divine grace.
14 They are now dead; they live no more; their spirits do not rise. You punished them and brought them to ruin; you wiped out all memory of them. 15 You have enlarged the nation, LORD; you have enlarged the nation. You have gained glory for yourself; you have extended all the borders of the land.
The cause opposed to God and his kingdom will sink at last.
16 LORD, they came to you in their distress; when you disciplined them, they could barely whisper a prayer.
Displaying our need for afflictions to wake-up. Before, prayers came forth drop by drop; now they pour it out like water from a fountain. Afflictions bring us to secret prayer.
17 As a pregnant woman about to give birth writhes and cries out in her pain, so were we in your presence, LORD.
Consider Christ as the Speaker addressing his church.
18 We were with child, we writhed in labor, but we gave birth to wind. We have not brought salvation to the earth, and the people of the world have not come to life.
His resurrection from the dead was an earnest of all the deliverance foretold.
19 But your dead will live, LORD; their bodies will rise – let those who dwell in the dust wake up and shout for joy – your dew is like the dew of the morning; the earth will give birth to her dead.
The power of his grace, like the dew or rain, which causes the herbs that seem dead to revive, would raise his church from the lowest state. But we may refer to the resurrection of the dead, especially of those united to Christ.
20 Go, my people, enter your rooms, and shut the doors behind you; hide yourselves for a little while until his wrath has passed by.
When dangers threaten, it is good to retire and lie hid; when we commend ourselves to God to hide us, he will hide us either under heaven or in heaven. Thus we shall be safe and happy in the midst of tribulations. It is but only for a short time, as it were for a little moment, it will seem like nothing when over.
21 See, the LORD is coming out of his dwelling to punish the people of the earth for their sins. The earth will disclose the bloodshed on it; the earth will conceal its slain no longer.
God’s place is the mercy-seat; there he delights to be: when he punishes, he comes out of his place, for he has no pleasure in the death of sinners. But there is hardly any truth more frequently repeated in Scripture than God’s determined purpose to punish the workers of iniquity. Let us keep close to the Lord, and separate from the world, and let us seek comfort in secret prayer.

A day of vengeance is coming on the world, and before it comes, we are to expect tribulation and suffering. But because the Christian looks for these things, shall he be restless and dismayed?
No, let him repose himself in his God. Abiding in him, the believer is safe. And let us wait patiently for the fulfillment of God’s promises.
Isaiah 26:5-21 | NIV