The remarkable emphasis [in the NT] on the need for a transformed life does not cancel out the priority of faith. Instead, it helps readers discern the authenticity of faith so that genuine faith can be distinguished from mere notional faith--faith that resides in the intellect but has not penetrated the heart and life. All good works flow from faith and thus do not become an occasion for human boasting. The changed lives of believers simply reveal the object of their trust. (Tom Schreiner, New Testament Theology [Baker 2008], 616).
That last sentence has a world of wisdom in it, and is something I've just been coming alive to in recent months.