(The prior post in this series may be found here.
In this section Marshall deals with the question of motivation, “we must have an inclination and propensity in our hearts” to do what God requires. There are two reasons for this. First, we will not act without the inclination. Second, the law of God itself requires love — and actual desire. It is not bare conduct which satisfies the will of God.
He begins by noting that this work of sanctification is too difficult to attain to without a satisfactory motivation:
And shall we dare to rush into the battle against all the powers of darkness, all worldly terrors and allurements, and our own inbred domineering corruptions, without considering whether we have sufficient spiritual furniture to stand in the evil day?
There are four “endowments” which Marshall lists as necessary. The first is “an inclination and propensity of the heart to the duties of the law”. This first element is the primary category. The remaining three elements matter as these support the desire to act:
[The duty required is not bare instinctual conduct” but such a one as it meet for intelligent creatures, whereby they are, by the conduct of reason, prone and bent to approve and choose their duty, and averse to the practice of sin. And therefore, I have intimated that the three other endowments [a new natures, confidence in the eternal state, and confidence they we will persevere] are subservient to this as the chief of all, which is are sufficient to make a rationale propensity.
Marshall here sets out a theory of human motivation: A human being will not fulfill the law of God (love of God and love of neighbor) unless he has a new nature, a “hope of heaven” and certainty that the hope is real for him.
Hope functions like magnetic north for a compass needle: Hope draws the attention and orders the conduct. We must have some hope and reasonable assurance to undertake any task. One will promise to come to see another because he has hope that it will be possible to make the trek and has sufficient reason to undertake the work. But no one (who is sane) would promise to be around the world in 30 seconds, or to travel back in time. Therefore, we need hope and we need those supernatural helps (a new nature and faith to lay hold upon what is promised to the new nature) to increase in holiness.
Next we will look at Marshall’s discussion of “inclination and propensity”.