After Christ ascended back to heaven (Acts 1:9-11), the eleven apostles returned to Jerusalem to await the fulfillment of the Lord’s promise concerning the outpouring of the Holy Spirit (cf. Lk. 24:49; Acts 1:8). Others convened as well, and during these days, Peter stood up and said:
“Brethren, it was needful that the scripture should be fulfilled, which the Holy Spirit spake before by the mouth of David concerning Judas, who was guide to them that took Jesus” (Acts 1:16).
The apostle then proceeded to quote Psalm 69:25 as an inspired prophecy of this circumstance. Subsequently, Matthias was selected to replace the fallen Judas.
There is a very important point within this context which relates to the concept of the inspiration of the Scriptures.
First, Peter affirms that David’s prophecy regarding the apostasy of Judas, and his subsequent replacement, was spoken by the Holy Spirit. The statement declares the divine origin of the message. It also indicates that the Holy Spirit is a divine Person.
Second, it asserts that David was the medium through which the Spirit operated in the conveyance of the message (cf. 2 Sam. 23:2). [Note: this also refutes the theory, advocated by some, that Psalm 69 was composed during the period of the Babylonian Captivity.]
Finally, the passage observes that the end result of this process was the production of “scripture.”
Thus, underline these phrases or terms: “scripture fulfilled,” “Holy Spirit spake,” and “mouth of David,” then, in the margin of your Bible, note these points:
Holy Spirit – Ultimate Source
Mouth of David – Medium Employed
Scripture – Final Result
This is a marvelous commentary on what was involved in the process of Bible inspiration.