In Isaiah 41, there is a section in which God challenges false gods to predict the future:

Isa 41:21 “Present your case,” says the LORD. “Bring forth your strong reasons,” says the King of Jacob.
Isa 41:22 “Let them bring forth and show us what will happen; Let them show the former things, what they were, That we may consider them, And know the latter end of them; Or declare to us things to come.
Isa 41:23 Show the things that are to come hereafter, That we may know that you are gods; Yes, do good or do evil, That we may be dismayed and see it together.
Isa 41:24 Indeed you are nothing, And your work is nothing; He who chooses you is an abomination.

Augustinian Christians point to this as some sort of proof that knowing the future is part of what makes God divine. It is easy to see where they get that conclusion. Verses 21-24 seem to be saying just that. But it is always a mistake to pull verses out of their context.

The previous 20 verses are making a concerted point:

Isa 41:2 “Who raised up one from the east? Who in righteousness called him to His feet? Who gave the nations before him, And made him rule over kings? Who gave them as the dust to his sword, As driven stubble to his bow?
Isa 41:3 Who pursued them, and passed safely By the way that he had not gone with his feet?
Isa 41:4 Who has performed and done it, Calling the generations from the beginning? ‘I, the LORD, am the first; And with the last I am He.’ ”
Isa 41:5 The coastlands saw it and feared, The ends of the earth were afraid; They drew near and came.
Isa 41:6 Everyone helped his neighbor, And said to his brother, “Be of good courage!”
Isa 41:7 So the craftsman encouraged the goldsmith; He who smooths with the hammer inspired him who strikes the anvil, Saying, “It is ready for the soldering”; Then he fastened it with pegs, That it might not totter.

Verses 2-7 inform the reader that God used His power to raise up an powerful army. The text is very clear. The army was powerful and God was responsible. God asks rhetorically: “Who raised one up?” “Who called?” “Who gave the nations?” “Who made him king?” “Who gave them to his sword?” “Who pursued them?” “Who has performed and done it?” The text is all about God’s power. God used His power to affect His plans, to bring them to past.

Isa 41:8 “But you, Israel, are My servant, Jacob whom I have chosen, The descendants of Abraham My friend.
Isa 41:9 You whom I have taken from the ends of the earth, And called from its farthest regions, And said to you, ‘You are My servant, I have chosen you and have not cast you away:
Isa 41:10 Fear not, for I am with you; Be not dismayed, for I am your God. I will strengthen you, Yes, I will help you, I will uphold you with My righteous right hand.’
Isa 41:11 “Behold, all those who were incensed against you Shall be ashamed and disgraced; They shall be as nothing, And those who strive with you shall perish.
Isa 41:12 You shall seek them and not find them— Those who contended with you. Those who war against you Shall be as nothing, As a nonexistent thing.
Isa 41:13 For I, the LORD your God, will hold your right hand, Saying to you, ‘Fear not, I will help you.’
Isa 41:14 “Fear not, you worm Jacob, You men of Israel! I will help you,” says the LORD And your Redeemer, the Holy One of Israel.
Isa 41:15 “Behold, I will make you into a new threshing sledge with sharp teeth; You shall thresh the mountains and beat them small, And make the hills like chaff.
Isa 41:16 You shall winnow them, the wind shall carry them away, And the whirlwind shall scatter them; You shall rejoice in the LORD, And glory in the Holy One of Israel.

Verses 8-16 speak that God will be with Israel. The text again is very explicit that God will save based on His power. “I have chosen.” “I will help you.” “I will make.” “I am your God.” “I will strengthen you.” “ I will help you.” “I will uphold you.” The entire text is about God being powerful and helping accomplish His plans in Israel. This block of text shows a shift in God talking about what He did do (v1-7 to what He will do). The idea is God established His power in v1-7 and now He is making promises for the future which can be trusted basted on that establishment.

Isa 41:17 “The poor and needy seek water, but there is none, Their tongues fail for thirst. I, the LORD, will hear them; I, the God of Israel, will not forsake them.
Isa 41:18 I will open rivers in desolate heights, And fountains in the midst of the valleys; I will make the wilderness a pool of water, And the dry land springs of water.
Isa 41:19 I will plant in the wilderness the cedar and the acacia tree, The myrtle and the oil tree; I will set in the desert the cypress tree and the pine And the box tree together,
Isa 41:20 That they may see and know, And consider and understand together, That the hand of the LORD has done this, And the Holy One of Israel has created it.

The next block of text again focuses on God’s power. God, in this text, points out explicitly that He is predicting, that He will accomplish, and then people can see the results and know God was the cause. As I have written before, prophecy is about power. God being able to affect His plans, shows us not God’s knowledge, but His power. That is what God says in Isaiah 41:20.

It is in this context that the text goes on to compare God to powerless idols:

Isa 41:21 “Present your case,” says the LORD. “Bring forth your strong reasons,” says the King of Jacob.
Isa 41:22 “Let them bring forth and show us what will happen; Let them show the former things, what they were, That we may consider them, And know the latter end of them; Or declare to us things to come.
Isa 41:23 Show the things that are to come hereafter, That we may know that you are gods; Yes, do good or do evil, That we may be dismayed and see it together.
Isa 41:24 Indeed you are nothing, And your work is nothing; He who chooses you is an abomination.

Notice God’s claim that their “work is nothing”. What God is saying is that idols are powerless. God is not comparing knowledge, but power. Although idols have no knowledge that is besides God’s point. Because prophecy is about power, God sees any failed prophecy as a sign of powerlessness. That is His primary claim against the idols, it is not that they are not omniscient.

This exact theme of power and prophecy is repeated time and time again in Isaiah 40-48.

Isa 46:10 Declaring the end from the beginning, And from ancient times things that are not yet done, Saying, ‘My counsel shall stand, And I will do all My pleasure,’

Isa 48:3 “I have declared the former things from the beginning; They went forth from My mouth, and I caused them to hear it. Suddenly I did them, and they came to pass.

God intimately connects His ability to accomplish things with His declared plans. That is what God wants Israel to believe. Prophecy is about power.