Jamieson, Fausset and Brown on Matthew 18:28

28. But the same servant went out, and found one of his fellow servants--Mark the difference here. The first case is that of master and servant; in this case, both are on a footing of equality. (See Mt 18:33, below.)

which owed him an hundred pence--If Jewish money is intended, this debt was to the other less than one to a million.

and he laid hands on him, and took him by the throat--he seized and throttled him.

saying, Pay me that thou owest--Mark the mercilessness even of the tone.