The knowledge of God is practical

People long for preaching that is practical, as they should. Sometimes, though, preachers move away from theocentric preaching in an effort to be practical.A.W. Tozer (quoted in Dallas Willard's book Renovation of the Heart), argues that right thinking about God is intensely practical. In face, we can trace many failures in living back to wrong thoughts about God. Tozer says:

A right conception of God is basic not only to systematic theology but to practical Christian living as well. It is to worship what the foundation is to the temple; where it is inadequate or out of plumb the whole structure must sooner or later collapse. I believe there is scarely an error in doctrine or a failure in applying Christian ethics that cannot be traced finally to imperfect and ignoble thoughts about God.

Willard writes:

Failure to know what God is really like and what his law requires destroys the soul, ruins society, and leaves people to eternal ruin. "My people are destroyed for lack of knowledge" (Hosea 4:6 NRSV),  and "A people without understanding comes to ruin" (4:14, NRSV). This is the tragic condition of Western culture today, which has put away the information about God that God himself has made available.Accordingly, the first task of Jesus in his earthly ministry was to proclaim God: to inform those around him of the availability of eternal life from God through himself…This is basic information for human life. It was then and is now.

Theocentric preaching is not impractical preaching.  Tozer, Willard, Packer and others establish that knowing God is one of the most important issues for practical living at any time.