Luke 21:36

But watch ye

(αγρυπνειτε δε). Αγρυπνεω is a late verb to be sleepless (α privative and υπνος, sleep). Keep awake and be ready is the pith of Christ's warning.That ye may prevail to escape

(ινα κατισχυσητε εκφυγειν). First aorist active subjunctive with ινα of purpose. The verb κατισχυω means to have strength against (cf. Matthew 16:18). Common in later writers. Εκφυγειν is second aorist active infinitive, to escape out.To stand before the Son of man

(σταθηνα εμπροσθεν του υιου του ανθρωπου). That is the goal. There will be no dread of the Son then if one is ready. Σταθηνα is first aorist passive infinitive of ιστημ.