Do not waste your spiritual energy
By doing spiritual practice one gets spiritual energy. If we use this energy, for example in the form of prayer to get worldly benefits then the spiritual energy gets depleted. The reason for this is that we draw upon our spiritual energy to orchestrate something for our worldly gains. Therefore instead our spiritual energy being utilised to enhance our spiritual growth we could even regress spiritually. There is no end to worldly difficulties and most of them are due to our destiny. With spiritual growth one derives increasing ability to face destiny and ultimately overcome it.