A.T. Robertson Commentary Luke 18:1

"And he spake a parable unto them to the end that they ought always to pray, and not to faint;" — Luke 18:1 (ASV)

To the end that (προς το δειν).

With a view to the being necessary , προς and the articular infinitive. The impersonal verb δε here is in the infinitive and has another infinitive loosely connected with it προσευχεσθα, to pray.

Not to faint (μη ενκακειν). Literally, not to give in to evil (εν, κακεω, from κακος, bad or evil), to turn coward, lose heart, behave badly. A late verb used several times in the N.T. (2 Corinthians 4:1,16, etc.).