b) Two other terms must also be clearly defined in order to arrive at a true conception of the gratuity of Christian grace. They are prayer for grace,(411) and a capacity or disposition to receive it.(412) To pray means to incite God’s liberality or mercy by humble supplication.
α) Despite the contrary teaching of Vasquez(413) and a few other theologians, congruous merit and prayer are really distinct because one can exist without the other. As the angels in Heaven are able to pray for us without earning a _meritum de congruo_, so conversely, all salutary works are meritorious even without prayer. Moreover, humble supplication does not involve any positive service entitled to a reward.
There is another important and obvious distinction, _viz._: between purely natural prayer (_preces naturae_) and supernatural prayer inspired by grace (_oratio supernaturalis_).
β) Capacity or disposition, especially when it takes the form of preparation, may be either positive or negative. Positive capacity is defined as “that real mode by which a subject, in itself indifferent, becomes apt to receive a new form.” Such a capacity or disposition always entails a claim to its respective form.
Positive capacity or disposition differs from both prayer or quasi-merit (_meritum de congruo_). Quasi-merit is entitled to a reward on the ground of fairness, whereas the _capacitas s. dispositio positiva_ is at most the fulfilment of an expectation based upon purely teleological considerations. Again, a reward can be bestowed upon some subject other than the one by whom the service was rendered, whereas the introduction of a new form necessarily supposes a subject disposed for or prepared to receive it. Thus only he who is hungry is disposed for the reception of food and entitled to have his craving satisfied.
Negative capacity consists in the absence or removal of obstacles that impede the reception of a new form, as when green wood is dried to become fit for burning.
c) There arises the important question whether or not divine grace is an object of merit, and if so, to what extent it can be merited by prayer and preparation.
It is of faith that the just man, by the performance of supernaturally good deeds, can merit _de condigno_ an increase in the state of grace and eternal glory, and that the sinner is able to earn justification _de congruo_. On the other hand, it is also an article of faith that divine grace is strictly gratuitous.(414) The two dogmas seem incompatible, but they are not, as will become evident if we consider that the good works of the just and the salutary works of the sinner are entirely rooted in divine grace and consequently the merits which they contain are strictly merits of grace in no wise due to nature.(415) When we speak of the absolute gratuity of grace, therefore, we mean the very first or initial grace (_gratia prima vocans_), by which the work of salvation is begun. Of this initial grace the Church explicitly teaches that it is absolutely incapable of being merited; whence it follows that all subsequent graces, up to and including justification, are also gratuitous,(416) _i.e._ unmerited by nature in strict justice, in so far as they are based on the _gratia prima_.