Of Prayer, by John Calvin, tr. Henry Beveridge [1845], at sacred-texts.com
This necessity our opponents do not at all consider. Therefore, when we say that believers ought to feel firmly assured, they think we are saying the absurdest thing in the world. But if they had any experience in true prayer, they would assuredly understand that God cannot be duly invoked without this firm sense of the Divine benevolence. But as no man can well perceive the power of faith, without at the same time feeling it in his heart, what profit is there in disputing with men of this character, who plainly show that they have never had more than a vain imagination? The value and necessity of that assurance for which we contend is learned chiefly from prayer. Every one who does not see this gives proof of a very stupid conscience. Therefore, leaving those who are thus blinded, let us fix our thoughts on the words of Paul, that God can only be invoked by such as have obtained a knowledge of his mercy from the Gospel, and feel firmly assured that that mercy is ready to be bestowed upon them. What kind of prayer would this be? "O Lord, I am indeed doubtful whether or not thou art inclined to hear me; but being oppressed with anxiety I fly to thee that if I am worthy, thou mayest assist me." None of the saints whose prayers are given in Scripture thus supplicated. Nor are we thus taught by the Holy Spirit, who tells us to "come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need" (Hebrews 4:16); and elsewhere teaches us to "have boldness and access with confidence by the faith of Christ" (Ephesians 3:12). This confidence of obtaining what we ask, a confidence which the Lord commands, and all the saints teach by their example, we must therefore hold fast with both hands, if we would pray to any advantage. The only prayer acceptable to God is that which springs (if I may so express it) from this presumption of faith, and is founded on the full assurance of hope. He might have been contented to use the simple name of faith, but he adds not only confidence, but liberty or boldness, that by this mark he might distinguish us from unbelievers, who indeed like us pray to God, but pray at random. Hence, the whole Church thus prays "Let thy mercy O Lord, be upon us, according as we hope in thee" (Psalm 33:22). The same condition is set down by the Psalmist in another passage, "When I cry unto thee, then shall mine enemies turn back: this I know, for God is for me" (Psalm 56:9). Again, "In the morning will I direct my prayer unto thee, and will look up" (Psalm 5:3). From these words we gather, that prayers are vainly poured out into the air unless accompanied with faith, in which, as from a watchtower, we may quietly wait for God. With this agrees the order of Paul's exhortation. For before urging believers to pray in the Spirit always, with vigilance and assiduity, he enjoins them to take "the shield of faith," " the helmet of salvation, and the sword of the Spirit, which is the word of God" (Ephesians 6:16-18).
Let the reader here call to mind what I formerly observed, that faith by no means fails though accompanied with a recognition of our wretchedness, poverty, and pollution. How much soever believers may feel that they are oppressed by a heavy load of iniquity, and are not only devoid of everything which can procure the favour of God for them, but justly burdened with many sins which make him an object of dread, yet they cease not to present themselves, this feeling not deterring them from appearing in his presence, because there is no other access to him. Genuine prayer is not that by which we arrogantly extol ourselves before God, or set a great value on anything of our own, but that by which, while confessing our guilt, we utter our sorrows before God, just as children familiarly lay their complaints before their parents. Nay, the immense accumulation of our sins should rather spur us on and incite us to prayer. Of this the Psalmist gives us an example, "Heal my soul: for I have sinned against thee" (Psalm 41:4). I confess, indeed, that these stings would prove mortal darts, did not God give succour; but our heavenly Father has, in ineffable kindness, added a remedy, by which, calming all perturbation, soothing our cares, and dispelling our fears he condescendingly allures us to himself; nay, removing all doubts, not to say obstacles, makes the way smooth before us.