Charles Ellicott Commentary Matthew 25:30

"And cast ye out the unprofitable servant into the outer darkness: there shall be the weeping and the gnashing of teeth." — Matthew 25:30 (ASV)

Cast ye the unprofitable servant... — We have so far considered the special punishment of sloth, but it is not complete without the solemn and emphatic recurrence of the “darkness” and “gnashing of teeth.”