Luke 17:31

Let him not go down

(μη καταβατω). Second aorist active imperative of καταβαινω with μη in a prohibition in the third person singular. The usual idiom here would be μη and the aorist subjunctive. See Mark 13:15; Matthew 24:17 when these words occur in the great eschatological discussion concerning flight before the destruction of Jerusalem. Here the application is "absolute indifference to all worldly interests as the attitude of readiness for the Son of Man" (Plummer).