Awhile back someone asked me how the Reformed doctrine that faith and obedience are conditions in the covenant of grace could be squared with the doctrine of justification by faith alone. Part of the problem, as Turretin pointed out long ago, is that “alone” can be grammatically ambiguous. “Justification only by faith,” would be less confusing because it could easly expand into “justification only by living faith.”

But here is one angle on how Scripture shows us that if faith is really faith it cannot fail to be obedient:

Children, obey your parents in the Lord, for this is right. “Honor your father and mother” (which is the first commandment with a promise), “that it may be well with you, and that you may live long on the earth” (Ephesians 6.1-3).

Honor your father and your mother, that your days may be prolonged in the land which the LORD your God gives you (Exodus 20.12).

Many people today seem to believe that the Law of God, as summarized in the Ten Commandments, is somehow subchristian. To an extant this is true, as is shown by Paul’s exhortation to children in his letter to the Ephesians. Paul alters the Fifth Commandment in order to apply it. The original words as written by God’s own finger are, incredibly, no longer an accurate statement of God’s promise to His children in regard to how they act toward their earthly parents. The original command came with a promise for long life in the Promised Land of Canaan; the Pauline revision promises long life even to those in Ephesus—and to Christians living anywhere else on earth.

Paul has articulated his fundamental principle for making this alteration elsewhere. In the letter to the Romans, he states, “For the promise to Abraham or to his descendants that he would be heir of the world [Greek: kosmos) was not through the Law, but through the righteousness of faith” (4.13). God promised Abraham a particular piece of land, and the Law put boundaries around it, but Paul tells us that the piece of land actually was a token of the whole cosmos. Now that Christ has come, the token is no longer needed because the full inheritance has been given.

However, when most people treat the Decalogue as subchristian, they usually mean something very different from the Apostle Paul. Some say that the Law was not for the Church, but for Israel. Some say that the Ten Commandments taught salvation by works and, in a roundabout way, also communicated that salvation must be by grace because, once anyone attempted it, they would soon discover Law-keeping was impossible.

Paul’s letter to the Ephesian children should give us second thoughts about such suggestions. In the first place, the Apostle Paul states that Christian children are under obligation, according to the Mosaic Law, to obey both their parents. Secondly, the Apostle Paul explicitly motivates such children to do so by saying that God will reward them—a reward he finds in the original Fifth Commandment, even though he changes the scope of that reward (to include the whole earth including Ephesus, not just Palestine).

Obviously, Paul was not teaching Christian children to believe that they had to earn salvation by works! The fact that the Apostle Paul would appeal to the authority of the Decalogue must mean that those commandments were never given so that people could earn anything from God. The Ten Commandments were never for merit or works-righteousness, but were only guides for what Paul calls “the obedience of faith” (Romans 1.5; 16.27).

It is worth pointing out that the Apostle Paul never sees a conflict between obedience and faith. He states, “Circumcision is nothing, and uncircumcision is nothing, but what matters is the keeping of the commandments of God” (First Corinthians 7.19); and, “For in Christ Jesus neither circumcision nor uncircumcision means anything, but faith working through love” (Galatians 5.6). Paul also warns of God’s judgment on “those who do not obey the gospel of our Lord Jesus” (Second Thessalonians 1.8). Indeed, in writing of unbelieving Jews, who were “broken off for their unbelief” (Romans 11.20), he says:

For just as you once were disobedient to God, but now have been shown mercy because of their disobedience, so these also now have been disobedient, in order that because of the mercy shown to you they also may now be shown mercy. For God has shut up all in disobedience that He might show mercy to all (Romans 11.20-32).

But not only is unbelief disobedient, but belief is obedience. Thus Paul writes of the conversion of the Romans:

What then? Are we to sin because we are not under law but under grace? By no means! Do you not know that if you present yourselves to anyone as obedient slaves, you are slaves of the one whom you obey, either of sin, which leads to death, or of obedience, which leads to righteousness? But thanks be to God, that you who were once slaves of sin have become obedient from the heart to the standard of teaching to which you were committed, and, having been set free from sin, have become slaves of righteousness (Romans 6.15-18; emphasis added).

The other writers in the New Testament concur. Luke writes that at one point “a great many of the priests were becoming obedient to the faith” (Acts 6.7). The author of Hebrews states that Jesus “became to all those who obey Him the source of eternal salvation” (Hebrews 5.9). He also writes of the Israelites in the wilderness, “they stumble because they are disobedient to the word” (Hebrews 3.18). John writes in his Gospel, “He who believes in the Son has eternal life; but he who does not obey the Son shall not see life, but the wrath of God abides on him” (John 3.36). In explaining what happens to those who disbelive, the Apostle Peter writes “they stumble because they are disobedient to the word” (First Peter 2.7).

In the preaching of the Gospel we see that Jesus can tell his hearers simply to “repent” (Matthew 3.2, 4.17), or to “repent and believe” (Mark 1.14). Likewise, the Apostles can simply command their listeners to “repent and… be baptized” (Acts 2.38), “repent and return” (Acts 3.19), “repent and turn to God, performing deeds appropriate to repentance” (Acts 26.20), or “believe on the Lord Jesus Christ” (Acts 15.11). Faith and obedience seem quite closely related to the point of being interchangeable.

Some say that there were two different promises given to Abraham—land (the “earthly Jerusalem”) and eternal life (heaven, “the heavenly Jerusalem”)—so that the Israelites were to keep their place in the land by the works righeousness of obedience to the Ten Commandments, but were given salvation from sin and future resurrection glory by faith alone. Supposedly this means that salvation (heaven, the resurrection) is given by grace, but works (which can allegedly never have anything to do with grace) were required for remaining in the Land.

This simply won’t work. The promise of land and eternal life are given to Abraham as one and the same promise (Genesis 15, 17). Likewise, the author of Hebrews states that the generation in the wilderness failed to enter the Promised Land because of “unbelief” (Hebrews 3.19).

What is worse, this idea makes the Gospel irrelevant to life on earth right now. It would mean that we can hope for heaven by grace but that, in this life, we must earn everything we get from God. Paul would then be telling children that their relationship to their parents is based on merit and “human effort” rather than by faith and grace. The Gospel, instead of transforming human relationships, would be irrelevant to human relationships! Church, family, work and all other areas of life would be run by performance rather than by grace.

But Jesus puts our life here and hereafter on the same basis:

Peter began to say to Him, “Behold, we have left everything and followed You.” Jesus said, “Truly I say to you, there is no one who has left house or brothers or sisters or mother or father or children or farms, for My sake and for the gospel’s sake, but that he shall receive a hundred times as much now in the present age, houses and brothers and sisters and mothers and children and farms, along with persecutions; and in the age to come, eternal life. But many who are first, will be last; and the last, first.” (Mark 10.28-31).

Likewise the Apostle Paul states, “bodily discipline is only of little profit, but godliness is profitable for all things, since it holds promise for the present life and also for the life to come” (First Timothy 4.8).

The fact is that, just like it was for Abraham, God’s covenant with us is not only for the life to come but for this life as well. The promise of the Fifth Commandment is for all of life. Children are not being told to think of obedience to their parents as holding a promise of only earthly prosperity, nor are they being taught to earn grace from God.

On the contrary, Paul wants the Christian children in Ephesus to live by faith both for this world and the next.

God’s promises are not statements about how much we can earn by doing good works. All our works—even our good works—apart from the intercession and shed blood of Christ could only send us to an eternal Hell. But precisely because we are commanded to believe God and trust him for salvation, the Law of God is to be obeyed (though things like circumcision are no longer to be simply imitated because Jesus has changed what is expected of believers since the time of the Old Testament period).

Jesus tells us to follow him. The way children commonly follow Jesus is by obeying their parents. Our motive for following Jesus should be that we trust him to save us. That is exactly what Paul tells the Ephesian children by the stipulation and promise of the Fifth Commandment. Christian children who obey their parents do so because they trust God’s promises to them in Jesus Christ.

In summary, the Law of Moses was only meant to be followed by faith, as the example of Moses himself proves:

By faith Moses, when he had grown up, refused to be called the son of Pharaoh’s daughter; choosing rather to endure ill-treatment with the people of God, than to enjoy the passing pleasures of sin; considering the reproach of Christ greater riches than the treasures of Egypt; for he was looking to the reward (Hebrews 11.24-26).

Much in the Law of Moses is no longer to be followed in the same way as it once was. The Apostle Paul states emphatically that it no longer matters if a believer is circumcised or not (First Corinthians 7.19; Galatians 5.6). Jesus revealed that the Mosaic dietary laws are no longer binding (Acts 10). But where the Law still applies, as it does to children who need to obey their parents, it does not encourage works-righteousness. Rather God’s commandments promote faith and trust in Christ Jesus for the future–both in this life and the life to come.

Our motive for obedience is nothing more nor less than that by which we are justified before God: Faith in Christ Jesus our Lord.