If God is slow in answering your request, and you ask but do not promptly receive anything, do not be upset, for you are not wiser than God. When you remain as you were before, without anything happening, it is either because your behaviour is not worthy of your request, or because the paths in which your heart was travelling were far removed from the aim of your prayer, or because your interior condition is far too childish, when compared with the magnitude of the thing for which you have asked.
St. Isaac of Nineveh [Syria], The Syriac Fathers on Prayer and the Spiritual Life.