Deuteronomy 1: God's Promises

Then I said to you, “Do not be terrified; do not be afraid of them. The LORD your God, who is going before you, will fight for you, as he did for you in Egypt, before your very eyes, and in the desert. There you saw how the LORD your God carried you, as a father carries his son, all the way you went until you reached this place.”

In spite of this, you did not trust in the LORD your God, who went ahead of you on your journey, in fire by night and in a cloud by day, to search out places for you to camp and to show you the way you should go. - Deut. 1:29-33 NIV

This is often so true of us.  We have seen God go before us; have seen him fight for us, but, when he reveals what he has promised to us, we quake with fear.  It's too much.  No matter how much we want to believe the promise, we hesitate to reach out and grasp it.  It's too big we cry, we can't do that.  There are giant obstacles standing in our way.  Sure, the reward would be sweet, but we don't have what it takes.  We take the burden of the vision from God and place it on our own shoulders, and sure enough, it is too heavy us to carry.

God's promises, promises for our future, are not dependent upon our abilities, but on him.
For I know the plans I have for you,” declares the LORD, “plans to prosper you and not to harm you, plans to give you hope and a future. Jer. 29:11 NIV
The promises, the visions, the desires of our hearts are placed in us by him, and he will carry through on what he has promised.