21I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain. (KJV)
"Righteousness," in the above verse, translates a Greek legal term and means "cleared of all guilt." Furthermore, the words "righteousness, righteous, just, justify, justified and/or justification," when used in your English Bible, are translations of the same Greek root above and still means, "cleared of all guilt."
"Frustrate" means "to make void." That is, Paul did not "make void" the grace of God. For him, Jesus' blood took care of the guilt and penalty for all his sins or it did not. If it did, then they were taken away by the grace of God.
For Paul, to add any other thing would frustrate the grace of God. Likewise, for him, to take away any thing from the blood of Jesus would also frustrate the grace of God.
In other words, Paul was completely satisfied that the grace of God, utilizing the blood of Jesus, had completely dealt with the guilt and unworthiness he may have had because of his sins. Paul spent his Christian life combating the peddlers of unworthiness.
He saw that our worthiness is based on the worth of Jesus' blood. His teaching on this great subject inspired the lines to the old song, "My hope is built on nothing less than Jesus' blood and righteousness." For Paul, salvation was based on the merits of Jesus blood plus nothing and minus nothing.
If God's grace, however, did not take care of Paul's guilt and unworthiness, then any hope he had of clearing his guilt and unworthiness must be based upon his own works of righteousness. In other words, he must keep Moses' law to obtain enough righteousness to be saved and blessed.
If this was true, howover, Paul plainly reasoned that Christ died for nothing. His death was useless. There was absolutely no point to it or in it.
"Vain," in the preceding verse, is an unusual word. It is a form of the Greek word for "gift." The form of the word used here, however, does not mean gift. It means "uselessly." It means "without a cause."
In other words, if Jesus' blood alone did not take away all Paul's guilt and unworthiness, Jesus died "for no cause at all." His death was "useless." There was "no point" to it. It "availed nothing." It "accomplished nothing."
Thank God, though, Jesus' blood did accomplish something. It did avail something. There was a point to it. It took care of the guilt and unworthiness produced by our sins.
We can still be healed and prospered. Jesus' blood paid it all. We are now as worthy as his blood. We are washed in it.
