Charles H. Spurgeon on Psalms 6:9

"The Lord hath heard my supplication." The Holy Spirit had wrought into the Psalmist's mind the confidence that his prayer was heard. This is frequently the privilege of the saints. Praying the prayer of faith, they are often infallibly assured that they have prevailed with God. We read of Luther that, having on one occasion wrestled hard with God in prayer, he came leaping out of his closet crying, "Vicimus, vicimus;" that is, We have conquered, we have prevailed with God." Assured confidence is no idle dream, for when the Holy Ghost bestows it upon us, we know its reality, and could not doubt it, even though all men should deride our boldness. "The Lord will receive my prayer." Here is past experience used for future encouragement. He hath, he will. Note this, O believer, and imitate its reasoning.