66:13-20 We should declare unto those that fear God, what he has done for our souls, and how he has heard and answered our prayers, inviting them to join us in prayer and praise; this will turn to our mutual comfort, and to the glory of God. We cannot share these spiritual privileges, if we retain the love of sin in our hearts, though we refrain from the gross practice, Sin, regarded in the heart, will spoil the comfort and success of prayer; for the sacrifice of the wicked is an abomination of the Lord. But if the feeling of sin in the heart causes desires to be rid of it; if it be the presence of one urging a demand we know we must not, cannot comply with, this is an argument of sincerity. And when we pray in simplicity and godly sincerity, our prayers will be answered. This will excite gratitude to Him who hath not turned away our prayer nor his mercy from us. It was not prayer that fetched the deliverance, but his mercy that sent it. That is the foundation of our hopes, the fountain of our comforts; and ought to be the matter of our praises.

18. If I regard iniquity in my heart—literally, "see iniquity with pleasure."