Matthew 23:18

(Verse 16 onwards) Woe to you, blind guides, who say, 'Whoever swears by the temple is nothing, but whoever swears by the gold of the temple is bound by his oath.' Fools and blind! For which is greater, the gold or the temple that sanctifies the gold? And, 'Whoever swears by the altar is nothing, but whoever swears by the gift that is on it is obligated.' Blind! For which is greater, the gift or the altar that sanctifies the gift? Therefore, whoever swears on the altar, swears on it and on all things that are above it.

Those who work in the fields of the gospel seek the hidden meaning of these passages of Scripture. We are not simply confiscating the higher parts of Scripture but rather looking toward its whole sense. As regards swearing, it is intended as a binding action, seeking to confirm the word concerning which something is sworn.Consider this analogy. Think of the altar as the heart and the temple as the whole of Scripture. The temple of God's glory, spiritually understood, is the divinely inspired Scripture. The gold refers to the meanings it conveys. To swear is to witness to the Scriptures, as a validation and confirmation of the word we speak. Therefore we ought to profess the whole sense of Scripture as a confirmation of the sense which we invoke in all of our words. Gold found outside the temple is not sanctified. Rather, that gold which is found in the temple is the measure of that which is outside it. Similarly the meaning which is found outside of the Scriptures is not holy, but it is contained in the meaning of the Scriptures. Only that sense of Scripture is sanctified which can be seen from within the temple itself, that is, within the whole of Scripture. The temple, that is, the reading of the Scriptures, makes a great and venerable sense, just as consecrated gold is valuable. So we ought not to swear by our own intellects to confirm our beliefs, as if we were creating witnesses that could judge according to the truth. But let us explore further the analogy of the temple, the gold and the altar. The altar is the place where a vow is sanctified. The altar in this passage is the heart of a man. What happens in the heart happens deeply within a person. Vows and gifts placed on the altar are clearly those placed upon the human heart. […]

Now an oath is in confirmation of somewhat that has been spoken. The oath here then may signify testimony of Scripture which we produce in confirmation of that word which we speak. So that Divine Scripture is the temple of God, the gold is the meaning which it contains. As the gold which is outside the Temple is not sanctified, so all thoughts which are without divine Scripture, however admirable they may seem, are not hallowed. We ought not therefore to bring any speculations of our own for the confirmation of doctrine, unless such as we can show are hallowed by being contained in divine Scripture. The altar is the human heart, which is the chief thing in man. The offerings and gifts that are hid upon the altar, are every thing which are done in the heart, as to pray, to sing, to do alms, to fast. Every offering of a man then is sanctified by his heart, by which the offering is made. There cannot therefore be a more honourable offering than the heart of man, out of which the offering proceeds. If then one's conscience does not smite him, he has confidence towards God, not by reason of his gifts, but so to speak because he has rightly ordered the altar of his heart. Thirdly, we may say that over the temple, that is over every Scripture, and over the altar, that is over every heart, there is a certain meaning which is called the Heaven, the throne of God Himself, in which we shall be able to see the things that are revealed face to face, when that which is perfect is come.

(Quæst. Ev. i. 34.) The temple and altar we may also understand of Christ Himself; the gold and the gifts, of the praise and sacrifice of prayer which we offer in Him and through Him. For not He by them, but they by Him, are sanctified.

Then he sets forth the second part of the tradition: and whosoever shall swear by the altar, it is nothing; but whosoever shall swear by the gift that is upon it, is a debtor.