Either Scripture establishes what the gospel is, calls people back to the gospel, and transforms God’s people with his Spirit-anointed gospel truth, shaping them into conformity with his Son, or it is but an empty boast. Sadly, some affirm sola scriptura in a sloganeering way, but rarely read Scripture and never meditate on it; or, worse yet, they thoughtlessly defy it.

When you come to the land that the LORD your God is giving you, and you possess it and dwell in it and then say, “I will set a king over me, like all the nations that are around me,” you may indeed set a king over you whom the LORD your God will choose. One from among your brothers you shall set as king over you. You may not put a foreigner over you, who is not your brother. Only he must not acquire many horses for himself or cause the people to return to Egypt in order to acquire many horses, since the LORD has said to you, “You shall never return that way again.” And he shall not acquire many wives for himself, lest his heart turn away, nor shall he acquire for himself excessive silver and gold.

And when he sits on the throne of his kingdom, he shall write for himself in a book a copy of this law, approved by the Levitical priests. And it shall be with him, and he shall read in it all the days of his life, that he may learn to fear the LORD his God by keeping all the words of this law and these statutes, and doing them, that his heart may not be lifted up above his brothers, and that he may not turn aside from the commandment, either to the right hand or to the left, so that he may continue long in his kingdom, he and his children, in Israel. (Deut. 17:14–20)

1. He must not acquire a great number of horses (v. 16). For “horses,” read “tanks”: the king is not to build his power by military might. The lust for power recurs in every age. The apostles themselves, misunderstanding the nature of the kingdom, sought the places of privilege and perceived power next to Jesus (Matt. 20:20–28), not discerning that the Master himself came not to be served, but to serve, and to give his life a ransom for many.
2. He must not make the people return to Egypt (v. 16). The prohibition reflects Israel’s political realities. God saved Israel by enabling her to escape slavery in Egypt. Sadly, Israel kept trying to play power politics, pitting friendship with Egypt over against friendship with one of the regional superpowers to the north (first Assyria, then Babylon). The desire for political security was something Israel valued more highly than the promises of God.
3. The king must not take many wives (v. 17). The issue was not just sex; it was networking. To marry one of the daughters of every regional two-bit city-monarchy meant it was far less likely that these tiny city-states would rebel against the king. Solomon became a master of such networking, the size of his harem simultaneously establishing his sexual prowess and securing his borders. Sadly, as God warned, his wives led his heart astray: pretty soon he was building pagan temples for them, even within Jerusalem itself. The desire for the kind of networking that guarantees social approval has not faded in the centuries since then.
4. And finally, he must not accumulate large amounts of silver and gold. Jesus himself insists that one cannot serve both God and money. What we must passionately desire becomes god for us. Money regularly signals freedom, prestige, power—and idolatry.

Look again at these four prohibitions: power, false security, desire for social approval through compromised networking, the pursuit of wealth—very much among the false gods still cherished and worshiped today.

So what, then, should the king make his top priority when he first assumes the royal throne? Should he audit the books of his predecessor? Rapidly form his cabinet, or at least appoint a secretary of state and a minister of defense? No, the first thing he is to do concerns the priority that God gives to Scripture. The king is to write out, by hand, a copy of “this law” (v.18). This is not a matter of downloading a text from the cloud to the hard-drive of a laptop without it going through anyone’s brain. This is laborious copying by hand.

What is included in the expression “this law” is disputed: it may be part of Deuteronomy, or all of Deuteronomy, or all of the Pentateuch. Whatever the size of text to be copied, the work is to be done so carefully that it becomes the king’s personal reading copy—a reading copy to be read and pondered by the king every day for the rest of his life. God provides three reasons for this priority: (1) the king will thereby learn to revere the Lord and his words; (2) he will thus be protected from thinking of himself as superior to others; and (3) he will not turn aside from God’s ways, to the right or to the left (17:18–20).

This passage indicates how highly the Word of God is valued, even at this early stage of canonical history. Joshua is told much the same thing: this book of the law shall not be tossed aside; rather, Joshua is to keep the Book of the Law on his lips, and meditate on it day and night, carefully doing everything written in it; for then he shall enjoy good success (Josh. 1:7–8).

The opening psalm in the Psalter declares, in the second verse, that the righteous person delights in the law of the Lord, and meditates on it day and night (Ps. 1:2). It takes constant meditation on holy Scripture to train one’s mind to think God’s thoughts after him. The point, in part, is that we are not what we think we are, but what we think, we are. That is why Paul tells the Romans that they must be transformed by the renewing of their minds(Rom. 12:1–2). So important is the valuation of Scripture that it trumps even our necessary food: God takes pains to teach Israel that “man does not live on bread alone but on every word that comes from the mouth of the LORD” (Deut. 8:3)—a lesson the Lord Jesus has already absorbed when he faces his own Satanic temptations (Matt. 4).

Sola scriptura is no mere slogan, a creedal point to be checked off with approval from a list.Either Scripture establishes what the gospel is, calls people back to the gospel, and transforms God’s people with his Spirit-anointed gospel truth, shaping them into conformity with his Son, or it is but an empty boast. Sadly, some affirm sola scriptura in a sloganeering way, but rarely read Scripture and never meditate on it; or, worse yet, they thoughtlessly defy it. Against all such failure, Deuteronomy 17:14–20 stands as a powerful bulwark. If these seven verses from Deuteronomy had been followed in the centuries before Christ, all of Old Testament history would have been different. Scripture—and, as we shall see, Scripture alone—is that important.

Here are eight reflections on sola Scriptura, reflections that are variously historical, theological, and pastoral.

1. Truthful and Reliable

The doctrine of sola Scriptura demands the truthfulness and reliability of holy Scripture. A document may be truthful but not in any useful sense authoritative. For example, a restaurant menu may tell the truth as to what is on offer, but we do not therefore speak of an authoritative menu. It is much more difficult to see how a document can be authoritative without being truthful—unless, of course, its “authority” is nothing more than a declarative fiction or an agreed convention.

For example, an organization may decide to operate under the authority of its charter, even if it is widely recognized that that charter needs revision because it embraces serious errors. For a document to be intrinsically authoritative in the matters of which it speaks, however, it must speak the truth, or its authority is pretentious folly.[1]

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