In this section, Watson makes one argument: To read the Scripture profitably, we must believe that the Scripture comes from God.

He supports that direction with the contention that the assertion of divine origin is not a bare assertion, but one grounded in reason. Thus, it is an interesting mix of presuppositional and evidentiary apologetic.

First, the basic direction

Give credence to the word written; believe it to be of God; see the name of God in every line. The Romans, that they might gain credit to their laws, reported that they were inspired by the gods at Rome. Believe the Scriptures to be divinely inspired. 2 Tim. 3:16: “All Scripture is given by inspiration of God.”

Before going further with this argument, we must realize the importance of this direction. If we do not believe the Scripture to be sacred, we cannot read it with any profit. All good which we receive from God comes through the conduit of faith, of trust and belief. If we do not trust or believe the words of Scripture, the words can never do us good. It did the disciples no good to be told that Jesus had risen from the dead, when they did not believe the story related by the woman. Luke 24:11.

Watson then turns to his evidence: He sets up his argument by testing the presuppositions against evidence. His basic argument runs as follows:

If the Scripture is divine, then it will have quality X.
It has quality X.
Therefore, the Scripture is divine.

Who but God could reveal the great doctrines of the Trinity, the atonement of Jesus Christ for sinners, the resurrection? Whence should the Scriptures come, if not from God?

He then makes a second argument which supports and develops the first.  The structure of the argument is:

If the Scripture were from someone beside it God, it would lack quality X.
It does not lack quality X.
Therefore, it is from God.

However, to make it more rhetorically emphatic, he phrases the argument, It is not from someone beside God, because it has quality X.

Sinners could not be the authors of Scripture; would they indite such holy lines, or inveigh so fiercely against the sins which they love?

Saints could not be the authors of Scripture; how could it stand with their sanctity to counterfeit God’s name, and put “thus saith the Lord,” to a book of their own devising?

Angels could not be the authors of Scripture. What angel in heaven durst personate God, and say, “I am the Lord?”

Then re-asserts his primary contention and adds additional divine qualities: antiquity, profundity, purity, harmony, efficacy.

Believe the pedigree of Scripture to be sacred, and to come from the Father of light. The antiquity of Scripture speaks its divinity. No human history extant reaches farther than Noah’s flood; but the Scripture treats of things before time. Beside, the majesty, profundity, purity and harmony of Scripture, show it could be breathed from none but God himself.

Add to this the efficacy the written word hath upon men’s consciences; by reading Scripture they have been turned into other men, as may be instanced in Austin, Junius, and others. If you should set a seal upon a piece of marble, and it should leave a print behind, you would say there was a strange virtue in that seal; so that, when the written word leaves a heavenly print of grace upon the heart, it argues it to be of divine authority. If you would profit by the word, you must believe it to be of God. Some skeptics question the verity of Scripture; though they have the articles of religion in their creed, yet not in their belief.

He ends with the restatement

Unbelief enervates the virtue of the word and makes it abortive; who will obey truths he does not believe? Heb. 4:2: “The word did not profit them, not being mixed with faith.”

Thomas Watson, “How We May Read the Scriptures with Most Spiritual Profit,” in The Bible and the Closet: Or How We May Read the Scriptures with the Most Spiritual Profit; and Secret Prayer Successfully Managed, ed. John Overton Choules (Boston: Gould, Kendall and Lincoln, 1842), 25–27.