A.W. Tozer emphasizes the uniqueness and finality of Christ's sacrifice, contrasting it with the Catholic practice of the Mass, which he argues erroneously suggests a perpetual sacrifice. He highlights that the New Testament clearly states that Christ's sacrifice was a once-for-all act, which cannot be repeated, as evidenced in Hebrews. Tozer points out that while priests may offer sacrifices daily, they cannot take away sins, whereas Christ's singular offering has perfected believers forever. He asserts that true forgiveness means there is no longer a need for any further sacrifice for sin.

In a friendly conversation with a Catholic priest I learned from the lips of this appointed spokesman of the Roman Church the philosophy of the Mass. He started with the blood offering of Abel and traced the practice of propitiatory sacrifice down through the Scriptures to the cross. "There must always be a sacrifice," he said, "and in the Mass the sacrifice is repeated each time the bread and wine are consecrated on the altar. At each celebration of the Mass the sacrifice of Christ is repeated." If the Mass rests upon the notion of the perpetual sacrifice then its foundation is only sand, for the New Testament is very clear that Christ's sacrifice is a once-for-all act and can never be repeated. Whatever tradition and dogma may say, thus saith the Lord. And by that will, we have been made holy through the sacrifice of the body of Jesus Christ once for all. Day after day every priest stands and performs his religious duties; again and again he offers the same sacrifices, which can never take away sins. But when this priest had offered for all time one sacrifice for sins, he sat down at the right hand of God (Hebrews 10:10-12). And if that is not plain enough the inspired writer further says, "Because by one sacrifice he has made perfect forever those who are being made holy" (verse 14); and, "where these have been forgiven, there is no longer any sacrifice for sin" (verse 18).