'A key rusteth that is seldom turned in the lock.'
It becomes hard work to stir it, for it becomes rusted into its place. Neglect of prayer makes prayer become hard work, whereas it should be a privilege and a delight. We cannot restrain prayer, and yet enjoy prayer. Frequency in this matter helps fervor, and constancy in it brings out the comfort of it.
Am I becoming slack in devotion? O Lord, forgive me, and save me from this grave neglect before it begins to eat into my soul and corrode my heart!"
--C.H. Spurgeon, Flowers From a Puritan's Garden