Answer

You ask a very good question. The context in 1 Corinthians 12, and your words "a private message from God," seem to suggest that this "word of knowledge" is a special miraculous gift in the same category as several of the other gifts listed in verses 9-10, i.e., healings, discerning of spirits, tongues, prophecy, and interpretation of tongues. It is the position of the OPC that all "those former ways of God's revealing his will unto his people [have] now ceased." Moreover, it is the teaching of Scripture and our Confession that God has revealed his will to the Church and has committed all that revelation to Scripture. (WCF, 1.1)

This is not just the teaching of the Confession but is the teaching of Scripture. First, consider Hebrews 1:1, "God, who at various times and in various ways spoke in time past to the fathers by the prophets." The explanation of this verse is a little difficult to grasp but it is very necessary. This verse clearly teaches that the OT prophecy should be understood as completed unit, "God … spoke." The Greek is quite clear. It employs the aorist tense, a tense that presents an action as a unit. That this unit is a past unit is clear from the phrase "in time past." Moreover, consider the words of Jesus to the Jews, "that on you may come all the righteous blood shed on the earth, from the blood of righteous Abel to the blood of Zechariah, son of Berechiah, whom you murdered between the temple and the altar" (Matt. 23:35). Thus, Jesus told them that they are held responsible for every murder mentioned in the Bible from the first, i.e., Abel, to the last, i.e., Zechariah. In doing this Jesus sets the bounds of the Old Testament as they were received in the Judaism of his day. Although the books were ordered differently than the order of our Christian Bible, the books included are the same. In other words, Jesus divinely limited Old Testament revelation to our Bible. These were the books implied in the statement in Hebrews 1:1.

Secondly, Hebrews 1:2, God "has in these last days spoken to us by his Son, whom he has appointed heir of all things, through whom also he made the worlds," is also offered as a proof text of the first paragraph of the WCF 1.1. Again, an explanation of the Greek is needed to understand how the fathers could use this verse to argue the closing of the NT canon. In this verse Hebrews clearly sets forth the closing of the NT canon when it says "has … spoken to us." Again, the aorist tense is used. Thus, the action envisioned, the speaking, is presented as a unit. In this case, the unit is not yet completed historically and the Holy Spirit does not intend to teach us that the book of Hebrews is not part of inspired writing, i.e., the unit was closed before this book was written. It should be obvious to the reader that Hebrews speaks with the authority of God, i.e., of Jesus. This is part of God's speaking "by his Son."

Therefore, we reformed believers deny all additions to inspired revelation whether by word of knowledge, tongues, or any other direct instruction from God. So, if this word of knowledge is taken to mean divinely granted knowledge or interpretation outside of Scripture, it has ceased. God has communicated himself and his will in the Scripture. It has all been committed to writing. The question is not whether God can give special messages today, but whether he would or will. He teaches us in the Bible that he can do this, but that he will not do so. He has spoken through the OT prophets and will not add to that communication. He has spoken through the Son and presents that speaking as a fixed, and now completed unit.

Again, consider Daniel 9:24, "Seventy weeks are determined for your people and for your holy city, to finish the transgression, to make an end of sins, to make reconciliation for iniquity, to bring in everlasting righteousness, to seal up vision and prophecy, And to anoint the Most Holy." In his magnificent commentary on Daniel, Dr. E. J. Young masterfully demonstrates that Daniel speaks of the earthly ministry of our Lord and its effects. One result of his ministry is that vision and prophecy have been sealed up.

Is it possible for Christians to "receive" a private message from God? Many believers say they have done so, but what does the Word of God teach?