1 Samuel 20:4 (NIV)
Whatever you want me to do, I'll do for you.
When we pray and ask God for things, we realize that we don't know what we should ask for. We go to our Heavenly Father full of requests, but when start praying our minds go blank and we're unable to ask Him for what we want. As saints we have to understand that God not only does what we need but also what we want, as long as we are in Him.