Mary, the mother of Christ, was a teenager living in Nazareth. An angel appeared to her and said, "Mary, you are highly favored of God. You will give birth to a child without knowing a man. He will be the Son of God."
Now, when God spoke this amazing promise to her, you might imagine the thoughts of defeat and doubt that were bombarding her mind. Thoughts saying, "You can't have a child without a man. That's impossible. That defies the laws of nature." If she would have looked at things just in the natural, she would have talked herself out of it. But Mary didn't consider her circumstances; she considered her God.
I love the way she answered back to the angel. She didn't say, "That sounds so far out. I just don't see how it could happen." No, she was bold. She told the angel, "Be it unto me even as you have said." In other words, "Let it happen. I am in agreement. If God says I'm highly favored, then I believe I'm highly favored. If God says the impossible is going to happen, I believe the impossible will happen."
That's the way we need to be when God puts a promise in our hearts. We may not see how it could work out in the natural, but we don't try to reason it out. We don't make excuses or dismiss it because we don't have it all planned.
Maybe you are facing an illness. God gives you the promise that with long life He will satisfy you. You could say, "Well, I don't know, Joel. The report doesn't look good. I've had this for five years. My great-grandmother died of the same thing." You could talk yourself out of it or you could say like Mary, "God, if You say I'm going to be well, I believe I'm going to be well."
Maybe you're struggling in your finances. You've run all the numbers. It doesn't look like you'll ever get out of debt. But because you're a giver, God gives you the promise He is going to open the windows of Heaven and pour out blessings that you cannot contain.
Don't dismiss it and start making excuses, "God, do You know where I work? God, do You know what the cost of living is? God, have You seen the stock market?" No, put those thoughts aside and follow Mary's example saying, "God, let it happen. I am in agreement. Be it unto me even as You have said!"