Called every one - As he was "steward," he had the management of all the affairs, and, of course, debts were to be paid to him.
Debtors - Those who "owed" his master, or perhaps "tenants;" those who rented land of his master.

So he called every one of his Lord's debtors,.... Either the Gentiles, who were greatly indebted to God, having sinned against him, and the law, and light of nature, at a great rate; into whose affections, houses, and palaces, the Jews found ways and means to introduce themselves; and, in process of time, got leave to have synagogues built, and their worship set up again: or else the Jews, their countrymen; since these were under those stewards, tutors, and governors, and were debtors to do the whole law; and had, by breaking the law, contracted large debts; and against whom the ceremonial law stood as an handwriting: these the steward called
unto him, and said unto the first, how much owest thou unto my Lord? and it is observable, that the debts of these men, of the first, lay in oil, and of the other in wheat; things much used in the ceremonial law, in the observance of which they had been, greatly deficient; see

fifty . . . fourscore--deducting a half from the debt of the one, and a fifth from that of the other.