Charles H. Spurgeon on Psalms 18:24-26

As you may see a proportion between sins and punishments which are the rewards of them, that you can say, Such a sin brought forth this affliction, it is so like the father; so you might see the like proportion between your prayers and your walking with God, and God's answers to you, and his dealings with you. So did David; "According to the cleanness of my hands hath he recompensed me," etc. His speech notes some similitude or likeness; as, for example, the more by-ends or carnal desires you had in praying, and the more you mingled of these with your holy desires, and the more want of zeal, fervency, etc., were found in your prayers, the more you shall, it may be, find of bitterness mingled with the mercy, when it is granted, and so much imperfection, and want of comfort in it. So says David in this same Psalm (verses 25, 26), "With the pure thou wilt show thyself pure." Pure prayers have pure "blessings; et à contra, "With the froward thou wilt show thyself froward." And again, as you in praying sometimes slackened and grew cold, so you might see the business in like manner to cool, and cast backward; as, When Moses's hands were down, Amalek prevailed; but when they were lifted up, Israel had the better. Exodus 17:12. God let him see a proportion, which argued his prayer was the means of prevailing. A man finds in praying that his suit sometimes sticks, and goes not on as he expected; this is because he gives not so good a fee as he was wont, and doth not ply God and solicit him; but on the contrary, when he was stirred up to pray, then still he found things to go well. By this a man may clearly see that it was the prayer which God did hear and regarded. Thus, likewise, when a man sees hills and dales in a business, fair hopes often, and then all dashed again, and the thing in the end brought to pass, let him look back upon his prayers. Didst not thou in like manner just thus deal with God? when thou hadst prayed earnestly, and thought thou hadst even carried it, then dash all again by interposing some sin, and thus again and again? Herein God would have you observe a proportion, and it may help you to discern how and when they are answered and obtained by prayer, because God deals thus with you therein in such proportion to your prayers. —Thomas Goodwin.