Albert Barnes Commentary Titus 1:15

"To the pure all things are pure: but to them that are defiled and unbelieving nothing is pure; but both their mind and their conscience are defiled." — Titus 1:15 (ASV)

Unto the pure all things are pure (Titus 1:15). (Romans 14:20).

There is probably an allusion here to the distinctions made regarding food and drink among the Jews. Some articles of food were regarded as "clean," or allowed to be eaten, and some as "unclean," or forbidden. Paul says that those distinctions ceased under the Christian dispensation. To those who had a conscience not easily troubled by scrupulous questions about ceremonial observances, all kinds of food might be regarded as lawful and proper. (Compare to 1 Timothy 4:4–5).

If a person habitually maintains a good conscience in the sight of God, it will be accepted by Him whether they abstain or do not abstain from certain kinds of food. .

This passage, therefore, should not be interpreted as proving that all things are right and lawful for a Christian, or that whatever they may choose to do will be regarded as pure. Instead, it primarily refers to distinctions in food, meaning that there was no sanctity in eating one kind of food and no sin in another, but that the mind was equally pure whatever was eaten.

The phrase has a proverbial quality, though I do not know if it was used in that way.

The principle of the declaration is that a pure mind—a truly pious mind—will not regard the distinctions of food and drink, or of festivals, rites, ceremonies, and days, as necessary to be observed in order to promote its purity.

The conscience is not to be burdened and enslaved by these things but is to be controlled only by the moral laws God has ordained.

However, there may be a somewhat higher application of the words: that every ordinance of religion, every command of God, and every event that occurs in Divine Providence tends to promote the holiness of one who is pure in heart.

Such a person can see a sanctifying tendency in everything and can derive from all that is commanded, and all that occurs, the means of making the heart more holy. While a depraved mind will turn every such thing to harmful use and make it the means of increasing its malignity and corruption, to the pure mind it will be the means of increasing its confidence in God and of making itself more holy. To such a mind, everything may become a means of grace.

But unto them that are defiled and unbelieving is nothing pure (Titus 1:15). Everything is made the means of increasing their depravity. No matter what ordinances of religion they observe, what distinctions of food or drink or days they regard, or what events of Providence occur, all are the occasion of increased depravity. Such distinctions in food they make the means of fostering their pride and producing self-righteousness. The mercies of God they abuse to indulge their own lusts, and the afflictive events of Divine Providence they make the occasion of murmuring and rebellion. Naturally corrupt at heart, no ordinances of religion and no events of Providence make them any better, but all tend to deepen their depravity.

A sentiment similar to this is found in classical writers. For example, Seneca, in Epistles 98, states: Malus animus omnia in malum vertit, etiam quae specie optimi venerunt. So again, in De Beneficiis (Book 5, Chapter 12): Quemadmodum stomachus morbo vitiatus, et colliques bilem, quoscunque acceperit cibos mutat—ita animus caecus quicquid illi commiseris, id onus suum, et perniciem facit.

But even their mind and conscience is defiled (Titus 1:15). It is not a mere external defilement—a thing they so much dread—but a much worse kind of pollution, one that extends to the soul and the conscience. Everything they do tends to corrupt the inner man more and more, making them truly more polluted and abominable in the sight of God. The wicked, while they remain impenitent, are constantly becoming worse and worse. They make everything the means of increasing their depravity; even those things that seem to pertain only to outward observances are made the occasion of the deeper corruption of the heart.