Only it appeared to me to be requisite to show in passing, that this book makes known to us this privilege, which is desirable above all others — that not only is there opened up to us familiar access to God, but also that we have permission and freedom granted us to lay open before him our infirmities which we would be ashamed to confess before men. Besides there is also here prescribed to us an infallible rule for directing us with respect to the right manner of offering to God the sacrifice of praise, which he declares to be most precious in his sight, and of the sweetest odour. There is no other book in which there is to be found more express and magnificent commendations, both of the unparalleled liberality of God towards his Church, and of all his works; there is no other book in which there is recorded so many deliverances nor one in which the evidences and experiences of the fatherly providence and solicitude which God exercises towards us are celebrated with such splendor of diction, and yet with the strictest adherence to truth, in short, there is no other book in which we are more perfectly taught the right manner of praising God, or in which we are more powerfully stirred up to the performance of this religious exercise.
Moreover although The Psalms are replete with all the precepts which serve to frame our life to every part of holiness, piety, and righteousness, yet they will principally teach and train us to bear the cross; and the bearing of the cross is a genuine proof of our obedience, since by doing this, we renounce the guidance of our own affections and submit ourselves entirely to God, leaving him to govern us, and to dispose of our life according to his will, so that the afflictions which are the bitterest and most severe to our nature, become sweet to us, because they proceed from him. In one word, not only will we here find general commendations of the goodness of God, which may teach men to repose themselves in him alone, and to seek all their happiness solely in him; and which are intended to teach true believers with their whole hearts confidently to look to him for help in all their necessities; but we will also find that the free remission of sins, which alone reconciles God towards us and procures for us settled peace with him, is so set forth and magnified, as that here there is nothing wanting which relates to the knowledge of eternal salvation.
—John Calvin’s Preface to the Commentary on the Psalms (HT: Matt Crutchmer)