Adam Clarke on Mark 9:43

Thy hand - foot - eye - cause thee to offend; - See the notes on Mat 5:29-30 (note).

The fire that never shall be quenched - That is, the inextinguishable fire. This clause is wanting in L, three others, the Syriac, and later Persic. Some eminent critics suppose it to be a spurious reading; but the authorities which are for it, are by no means counterbalanced by those which are against it. The same clause in Mar 9:45, is omitted in BCL, seven others, Syriac, later Persic, Coptic, and one Itala. Eternal fire is the expression of Matthew.