Kenneth Copeland once said in an interview that he does what he does because "it works" whatever that means.
I know because I watched the interview.
The word "it" is referring to the word of God.
The reason why both He and I say "it works", is because we know it is the word of God itself that does the work that WE send IT to do.
The sendee is subject to the sender, because for one, greater is the one who sends than the one that he sent, and two, the sender is the who formed/framed/made the program or orders that was given to the servant/solder/word of God.
Even as it is the word of God itself that saves us,
NOT GOD HIMSELF, but His word,
the same said word, casts out devils, heals the sick, cleanses the lepers, and raises the dead.
But having said all that, if you don't
KNOW beyond
ALL DOUBT, then that servant/soldier/word will not do what it was sent to do by you.
And that's not all.
If you fail to act on what you believe in your heart, the same said word will be as a lifeless dead body. It will NOT work or do anything you sent it to do. Which is why many people think God says no.
Many Christians both think and say they believe or have faith when they pray, when both they and you, do NOT.
How do I know?
I know from what you wrote. You don't believe the promises in God's word, and therefore you cannot have faith in God to answer your prayers. If you did, you would base your prayers on them and talk faith or positively, at the very least.
And because you most likely don't believe death is in the power of your own tongue, you most likely curse both yourself and family members. Which proves the truth of God's word.
That being, irrespective of God's will, you are the cause of some, if not most, of the bad things that happen to either you or your loved ones.
This faith stuff does indeed work. To the good, it works for them for good, and to the bad or corrupt, it works against them for bad.
Mat 12:35 A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.
Who brought forth both the good and bad things?
THE MAN DID HIMSELF.
NOT GOD OR THE DEVIL, BUT THE MAN WHO SPOKE OUT OF THE ABUNDANCE OF HIS HEART.
God not only means what He says, He is faithful to make sure it is done. Whether it be for good or evil, blessing or cursing, life or death.
What you say without thinking, is what you believe in your heart. And if all you believe is what's in the natural, then you are the one sanctioning the natural to work in your life, while removing or preventing God, through His word, from doing a good work in your life and/or that of a loved one's life.