Titus 1:15-16

¹⁵To the pure, all things are pure, but to those who are corrupted and do not believe, nothing is pure. In fact, both their minds and consciences are corrupted. ¹⁶They claim to know God, but by their actions they deny him. They are detestable, disobedient and unfit for doing anything good.

These commands, or rules (Colossians 2:20-23), mentioned in v14 probably included kosher food concerns and necessity of ritual cleansings for purity; thus Paul declares, “To the pure, all things are pure,” announcing that all are pure in Christ alone. Sanctification does not happen by exterior obedience to manmade rules; rather, it happens through inward holiness blossoming into outward blamelessness. The Spirit works on the heart through the word, and so sound doctrine is essential to Christian progress in growth, in sanctification. See 1 Timothy 4:3-5; the false teachers were probably prohibiting the use of certain things considered impure to them, were in reality perfectly pure according to sound doctrine. Paul also rebukes the false teachers as “corrupted” precisely because they “do not believe.” Therefore, nothing to them is pure, for everything they do as unbelievers is sin (Romans 14:23; Hebrews 11:6); though outwardly pure, perhaps, like the Pharisees, they are inwardly corrupted in both mind and conscience, “whitewashed tombs / walls” (Matthew 23:27; Acts 23:3). The Christian, on the other hand, may appear to them as impure outwardly, but since their inside is pure through faith in Christ and the imputation of His righteousness, they, in fact, are the pure, not the false teachers who claim to be so. Instead, as v16 declares, the false teachers are detestable, disobedient, and unfit for doing anything good – precisely because they deny God by their actions, despite claiming to know Him. A person’s actions reveal their heart. By their fruits you will know them.

To summarize v15-16, Paul upholds Christian liberty and freedom, but also the necessity of inward and, consequently, outward purity. Paul reveals that both the doctrine (internal knowledge of mind and conscience) and the behavior (external actions) of the false teachers are corrupted, detestable, and worthless (2 Timothy 3:2-5). Calvin says, “In the first clause of this verse he upholds Christian liberty, by asserting, that to believers nothing is unclean; but at the same time he indirectly censures the false apostles who set no value on inward purity, which alone is esteemed by God. He therefore rebukes their ignorance, in not understanding that Christians are pure without the ceremonies enjoined by the Law; and next he chastises their hypocrisy, in disregarding uprightness of heart, and occupying themselves with useless exercises… The mind denotes the understanding, and the conscience relates rather to the affections of the heart. But here two things ought to be observed; first, that man is esteemed by God, not on account of outward works, but on account of the sincere desire of the heart; and, secondly, that the filth of infidelity is so great, that it pollutes not only the man, but everything that he touches.”