Albert Barnes 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)

A parable. See Barnes on Matthew 13:3.

To this end. To show this.

Always. At all times. That is, we must not neglect regular, established times for prayer; we must seize opportunities presented by remarkable providences—such as afflictions or notable blessings—to seek God in prayer; we must always maintain a spirit of prayer, or be in a proper disposition to lift up our hearts to God for His blessing, and we must not grow weary even if it seems our prayer is not answered.

Not to faint. Not to grow weary or give up. The parable is designed to teach us that, even if it appears for a long time that our prayers are unanswered, we should persevere, and not grow weary in supplication to God.