Isaiah 26:3 You will keep in perfect peace those whose minds are steadfast, because they trust in you.
God does not just dish out peace to everyone who asks for it because many people who ask things from God don’t actually believe anything will be done! God requires us to believe with our hearts that He is God.
Believing is not just something we say in our heads or say out loud; after all anyone can say that they believe in God without actually meaning it.
But for those who do believe in their hearts that God is alive and listening to their prayers, they will get to know that peace that only God can give because they will get to know God personally.