As someone who played in jazz bands for years, I found this to be a creative analogy.
God is the musician; Isaiah, Paul, and Peter are the various instruments he plays, each with its distinct sound.
Nobody listening to Louis Armstrong playing in a jazz club would have asked whether it was Louis or his trumpet making the music. The breath and tune came from Armstrong, but the trumpet was the instrument through which his breath flowed in order to become audible. Likewise, the biblical authors are instruments of revelation—a trumpet here and an oboe there—each making its own sound. But the musician, the skilled artist who fills them with his breath and ensures the tune is played correctly, is the Holy Spirit.