A.T. Robertson Commentary Luke 14:35

"It is fit neither for the land nor for the dunghill: [men] cast it out. He that hath ears to hear, let him hear." — Luke 14:35 (ASV)

Dunghill (κοπριαν). Later word in the Koine vernacular. Here only in the N.T., though in the LXX.

Men cast it out (εξω βαλλουσιν αυτο). Impersonal plural. This saying about salt is another of Christ's repeated sayings (Matthew 5:13). Another repeated saying is the one here about having ears to hear (Luke 8:8; 14:35, Matthew 11:15; Luke 13:43).