Hebrews 10:26 says, "For when we sin willfully after receiving the full knowledge of the truth, there no longer remains a sacrifice for sins." Some Christian teachers have taught inaccurately that this verse means if we sin willfully we cannot be forgiven. This is not the proper understanding. The proper understanding is that all of the sacrifices in the Old Testament were fulfilled when the Lord Jesus died on the cross. To go back to those animal sacrifices is a sinful thing to the Lord. To go back to Judaism after the sacrifice of the Lord Jesus on the cross is to sin willfully. As far as God is concerned there is no more sin offering, because His Son offered Himself once for all.
Paul also indicated that if the Hebrew Christians went back to offer the animal sacrifices, God would judge them (Heb. 10:27). Their going back would make the blood of Christ a common thing. But His blood is not common, like the blood of an ox or a lamb. Actually, the blood of the animal sacrifices could not redeem, but the blood of Christ can redeem. To go back to Judaism and offer the blood of an ox or a sheep for the sacrifice of sin is to make the blood of Christ common. This will bring in God's judgment.
In addition to this, to go back to Judaism and the animal sacrifices would constitute a kind of disobedience to the indwelling Spirit. In verse 29 Paul spoke of insulting the Spirit of grace. To go back to Judaism is to insult the Spirit of grace. This portion of the Word shows that once we have enjoyed and participated in the New Testament way, we must enjoy it to the uttermost. We should not go back to the old way, to the Old Covenant. To go back to the old way is a sinful thing to the Lord and will bring His judgment upon us. To go back would make the Lord's blood something common and would constitute a kind of disobedience to the indwelling Spirit.
Now we come to the fifth section of the book, which begins with chapter eleven. In this section Paul shows us the way of faith. As we go on with the Lord, we must take faith as our way. On our way we have many surrounding, encompassing witnesses. The way of faith is very prevailing. Here we have the Lord Jesus as the author and finisher of our faith. We all must look to Him. We should not be concerned for the surrounding situations. We simply look to the Lord Jesus as our way to go on. If we will not look away to the Lord Jesus as our way, we will lose something and suffer something. Since we have received a kingdom which cannot be shaken, we must take grace to go on in a positive way. We should not be disturbed with difficult situations and circumstances. Go on by faith. The Lord Jesus is the Leader and the Finisher of our faith. We simply look unto Him. By this we will be strengthened to go on.