I always find encouragement in reading prayers. One great resource for reading prayers is The Valley of Vision, a collection of Puritan prayers. Another good resource is Prayers of John Calvin from his Commentary on Hosea. This small collection is available for free viewing and download from Monergism.com.
Below is one of Calvin’s prayers from the collection.
Grant, Almighty God, that as thou hast not only of late adopted us as thy children, but before we were born, and as thou hast been pleased to sign us, as soon as we came forth from our mother’s womb, with the symbol of that holy redemption, which has been obtained for us by the blood of thy only begotten Son, though we have by our ingratitude renounced so great a benefit, – O grant, that being mindful of our defection and unfaithfulness, of which eve are all guilty, and for which thou hast justly rejected us, we may now with true humility and obedience of faith embrace the grace of thy gospel now again offered to us, by which thou reconciles thyself to us; and grant that we may steadfastly persevere in pure faith, so as never to turn aside from the true obedience of faith, but to advance more and more in the knowledge of thy mercy, that having strong and deep roots, and being firmly grounded in the confidence of sure faith, we may never fall away from the true worship of thee, until thou at length receives us in to that eternal kingdom, which has been procured for us by the blood of thy only Son. Amen.