John Murray explained the relationship between systematic theology and practical theology so well in his charge to Edmund Clowney when Clowney was installed as professor of practical theology at Westminster Theological Seminary (1963). Here’s what Murray said:
Practical theology is principally systematic theology brought to practical expression and application. And this means the whole counsel of God brought to bear upon every sphere of life, particularly upon every phase of the life and witness of the church. He would be a poor theologian indeed who would be unaware of, or indifferent to, the practical application of God’s revealed counsel. But likewise, and perhaps more tragically, he would be a poor exponent of practical theology who did not know the theology of which practice is the application. I charge you to make it your concern to be the instrument of inflaming men with zeal for the proclamation of the whole counsel of God and of doing so with that passion and power without which preaching fails to do honor to the magnitude of its task and the glory of its message.John Murray, Collected Writings, vol. 1, p. 108.
Covenant Presbyterian Church (OPC)
Hammond, WI, 54015