Sometimes God asks us to do things which, from our earthly perspective, make no sense. Many times it is only after we have taken the step of faith and obeyed that we begin to understand what it is that God is doing. Consider the following conversation which may or may not have taken place in Exodus Chapter 17.
Moses - God, we have taken a poll and the majority of the Israelites are really thirsty and we were wondering if you could show us where some water is.
God - Take your staff and strike that rock.
Moses - I understand that you typically know what you are talking about, but our research has indicated there may be an aquifer under the ground near here and we just need to find where it is so that we can dig a well.
God - Strike the rock.
Moses - I hear what you are saying and I think typically that would be a great idea, but historically we have found that large boulders contain, well, rock.
God - Strike the rock.
Moses - I feel as though we aren't communicating here. We have 100 people with all the shovels and equipment ready to dig for water, we just need to know where to dig. Everyone knows you dig for water in the desert. I mean it would look really foolish for me to stand up in front of everyone and begin banging on that rock. What would they think?
God - STRIKE THE ROCK! I want to show you my POWER and my GLORY. This is about me, not you!