This is the passage in Numbers where 12 men from the twelve tribes of Israel go out into Canaan to observe the people and the land. When they come back, all but two of the men (Caleb and Joshua) create fear within the community, claiming that the people of Canaan were far too big, that they would not be able to defeat them.
Now. God did not send these men into the land to assess the situation in order to change their plans, He sent them in to show them what He was giving to them. They forgot what He had promised in the beginning, and because they forgot, they grew fearful, and because they grew fearful they disobeyed God. In the end, that generation did not get to see the promised land. Instead, they wondered the desert for 40 years until the last of them were dead. Then, God fulfilled His promise through Joshua, who lead them into the promised land, taking on the supposedly impossible to defeat Canaanites.
I need to remember this in my day to day life as well. That if God promises me something, my short comings will not get in the way. In my weakness, He is strong. How cool is that?