Within the scope of merit are the two forms of condign and congruous merit. Both are distinct from another, and yet they have an integral relationship with one another. The two merits are gained from the Christian and are payable in Heaven in different ways. Regarding these John Hardon writes, “Synonymous with condign is deserved, adequate, justly due; and with congruous that which is fitting or becoming. On the difference between the two rests the whole theology of supernatural reward” (Hardon Ch. 9).
A good example of condign merit can be found in the parable of the vineyard in Matthew chapter 20. The landowner hires laborers and agrees to hire them for the daily wage. The landowner goes out later in the day to get more laborers, and when the time came to collect their wages they all got the same. The agreement for all was the usual daily wage. It can only be received in a state of grace and free will must be used to gain it (Stevens 73). Condign merit comes from the fact that God has promised a reward. Grace moves one to action and free will has to be used (STII, Q114, A3).
Congruous merit is a type of action that gains merit for others. Like condign merit, congruous merit can only be earned for others if one is in a state of grace (Hardon Ch. 9). We see this clearly when we perform prayer and fast for the poor souls in purgatory. However congruous merit can be gained even if one is not in a state of grace. Those in a sinful state can merit congruous graces that they need to enter back into a relationship with God (Hardon Ch. 9). The person opens themselves to embrace the grace of God and that leads them to repentance.
As previously stated, condign and congruous merit are distinct but have an integral relationship. Congruous merit arouses the soul to move towards God, and this movement can lead one to condign merit. Condign merit comes to those in a state of grace, but one is not able to gain condign merit without first having gained congruous merit. This is how the two are linked in such a way because they assist in leading one towards the beatific vision.
Aquinas, Thomas. Summa Theologia. Trans. Thomas Gornall. Blackfriars, St. Joseph, IN: Ave Maria Press, 1981. Accessed September 9, 2018.
Hardon, John. History and Theology of Grace. Ann Arbor, MI: Sapientia Press, 2005.
Stevens, P.G. The Life of Grace. New York: Prentice Hall, 1963.