From JC Ryle Quotes:
Would you have more faith? Do you find believing so pleasant that you would like to believe more? Then take heed that you are diligent in the use of every means of grace – diligent in your private communion with God – diligent in your daily watchfulness over time, temper, and tongue – diligent in your private Bible reading – diligent in your own private prayers. It is vain to expect spiritual prosperity, when we are careless about these things. Let those who will, call it over-precise and legal to be particular about them. I only reply, that there never was an eminent saint who neglected them.
~ J.C. Ryle