Faith isn't believing God will do what you say. Faith is believing what God says He will do.
Wow, you are so close in one point and yet so wrong in the other.
Faith is actually not believing, which is a verb, but is the person, place, thing, and/or situation or circumstance, which is a noun.
Faith IS the very thing you envision.
Paul said it is the substance or material of the thing you envision.
Where Faith doesn't require any action to have, believing does.
However, without believing, the substance or material will lie dormant and dead, as faith requires believing for it to manifest in the natural.
And the kind of believing God teaches in his word, requires some type of corresponding physical act to said belief.
You cannot, " just believe", and have your faith manifest in the natural, as nothing will happen.
And another thing concerning God's kind of believing, is to Believe it is, you have it now, or it is done or has already happened when you prayed or spoke, which means, BEFORE you see it, feel it, hear it, taste it, experience it, or manifests in the natural.
That's not an easy thing to do for an adult.
And all this hinges on believing God will perform his word or do what he said he will do in His word.
So if I bind the strong man and command the thing to come out in the name of Jesus, since it is not me doing the actual work to drive the thing out, but God doing it through his word, which is our power, strength, and ability, God gets the glory.
Now the reason why I say it is okay to tell God what to do, is because I am the one directing and sending his word, or the word of faith, which is the spoken word of God, to do what I commanded it to do.
So I'm not actually telling or demanding God Himself do this for me, as I'm not actually speaking to God, but I am more directing his hand by saying what I want done in faith.
And so to my second point, you still have to have faith in the words you just formed and spoke.
Without faith in your own words, they're just empty, idle, inactive, and dead words.
Without God acting on our word, they are, as I said, just inactive, empty, idle, and dead.