Scripture on debt and equality

The Gospel readings in recent weeks of the Lectionary Calendar coincidentally touch upon some of the themes that I've been reflecting on in Grotius and Cicero.  One is in the Parable of the Day Laborers (Matt.20:12):

This is a very good example of the 'disproportionality' or 'unevenness' that Grotius seems to think is obligatory under the law of charity, though not under the law of nature.  This is purely speculation now, but as I was listening to the Gospel reading, this particular verse caught my attention.  Something I will need to follow up on.  By the way, the word, 'equal,' in the Vulgate is 'pares.'  The Greek New Testament has ἴσους. 

The other text is Matt.18:23-35 on debt a model for forgiveness.

Another text that caught my attention, where Christ favors the disproportionality of grace and charity.  I am not a theologian, and surely, over the centuries of theological scholarship and commentary, the economics of the Gospels in these Parables (there are others too) must have been discussed at length - in this spirit, please forgive my ignorance.  Anyway, this will be another item to follow up on.  There is an emerging gap in modern natural law reasoning between what natural law enjoins (proportionality - suum cuique tribuere: natural law would have no problem with the outcome in Matt.18:30 - the debtor ending up in prison) and what the law of charity requires (disproportionality in the debtor's favor).