Isaiah 26:3
The book of Isaiah was written by the prophet Isaiah, who served as a messenger to the people of the Southern Kingdom of Judah for more than fifty years (around 740 to 686 BC).
His calling was to point out the sin that ran rampant amongst the people of Judah at this time, and he often spoke God’s words directly to the four kings who reigned during his ministry.
He accomplished his calling both by preaching the truth of Judah’s present circumstances and by prophesying about their future.
Covering everything from impending national judgment to the coming of Christ to the hope of a new heaven and a new earth.

Isaiah 26:3 Meaning
One of the major themes in Isaiah is that as God’s people obey his will by trusting in him, they will find peace and prosperity in their lives.
This didn’t mean the people would never experience hardship or disharmony; in fact, they were experiencing much of both.
However, a prevalent sin amongst the people of Judah during this time was building up wealth by exploiting the poor and marginalized people.
God saw the people were not trusting him to take care of them and were attempting to find peace and security on their own, even if it meant taking cruel advantage of others who were already at risk in their community.
The original Hebrew does not contain the word for perfect prior to peace but instead actually repeats itself by saying “peace, peace.”
God and his inspired writers always use repetition in the Bible with specific intentions, and here, this repetition is interpreted to mean real, true, constant, and lasting peace.
The people of Judah did not live in a peaceful time, so they were tempted not to remain steadfast in their knowledge of whom God had proven himself to be and what he had promised them.
Isaiah is reminding them that their sinful attempts to find peace through other means will never lead to the perfect peace God can give them.
Isaiah 26:3 Application
Like the people of Judah, we all go through times when peace feels hard to find. Sometimes you may try to control your external or internal, temporary or permanent peace by taking matters into your own hands.
Running away from unpeaceful situations, or getting caught in mental patterns of worry and anxiety.
God wants you to know that, while worldly peace may indeed be hard to find, his perfect peace is always available to you.
When you steadfastly set your mind on him, day to day and moment by moment, and trust in him more than anything else.
He will not only give you the peace you seek; he has the power to keep you in a state of true peace no matter what happens.
“The LORD is my light and my salvation —whom shall I fear? The LORD is the stronghold of my life— of whom shall I be afraid?”