Jamieson, Fausset and Brown on Mark 9:50

50. Salt is good; but if the salt have lost his saltness--its power to season what it is brought into contact with.

wherewith will ye season it?--How is this property to be restored? See on Mt 5:13.

Have salt in yourselves--See to it that ye retain in yourselves those precious qualities that will make you a blessing to one another, and to all around you.

and--with respect to the miserable strife out of which all this discourse has sprung, in one concluding word.

have peace one with another--This is repeated in 1Th 5:13.