A selection from a letter by the reformer John Calvin to the church of Geneva, of which he had been pastor until banished by the civil authorities. He was in Strasbourg preaching to a community of exiles. It would be three years before he returned to Geneva. His letter was filled with spiritual advice and heart-warming consolation. It was written October 1, 1538.
Above all, take heed that you watch unto prayer; for if your whole expectation rests upon God, as it ought, there is good reason to infer that your heart should be daily lifted up to heaven in calling upon the Lord, and earnestly supplicating the mercy which you hope to obtain from himself. Understand, moreover, that if he delays to grant the desire of his children, and does not immediately manifest himself in the time of need for their deliverance, it is generally because he wishes to stir them up and urge them on to supplicate his favour. However confident we may be in making a vain-glorious boast of putting our trust in him, it will be of no avail while we do not offer any proof of it, by flying to him as our refuge, in prayer. Besides, it is a matter of tried experience, that there is never such an earnest fervency of stayed affection and ardour in our prayers as there ought to be, save when we persevere therein without ceasing.
John Calvin: Tracts and Letters, edited by Jules Bonnet and translated by David Constable, first published by the Presbyterian Board of Publication, 1858, republished by The Banner of Truth Trust, 2009, vol. 4, p. 88.