I. This parable does not teach us to pray. There is no need that it should. Like the belief in a God, the moral sense of right and wrong, the hope of immortality, the expectation of a judgment, prayer seems as much an instinct of the soul as breathing, eating, drinking are instinctive actions of the body, which we need neither to be told, nor to learn, to do.
II. It teaches us how to pray. The point here is the fervour and frequency, the constancy and perseverance, or what has been called, in one word, the importunity of prayer. This implies, at least on our part, stated daily praise. To omit prayer is to go to battle, having left our weapons behind us in the tent; is to go to our daily labour without the strength imparted by a morning meal; is to attempt the bar where breakers roar and rocks hide their rugged heads without taking our pilot on board.
II. The parable teaches persevering prayer. It is hard, fainting work praying. It is harder to pray than to preach. We do not believe what we profess, nor feel what we say, nor wish what we ask; or, if we do, we do not take the right way of getting it. And how can we expect God to answer prayer when He sees, what we ourselves might see, that we are not earnest? If we were we would be urgent, praying in the house, by the way, on our beds, at our business prayer sounding or silent, a constant flowing stream. By constant dropping the water wears a hole in the hardest stone. And who, as he sat on a jutting crag, amid the spray of the roaring, flashing cataract, has not marked how by her constant flow the river has polished its rugged sides, and worn out smooth runnels for its streams. So, as it is only perseverance in grace that can carry us up to heaven, it is only perseverance in prayer that can bring its blessings down. Such is the plan of redemption, the ordinance of God. "The kingdom of heaven suffereth violence, and the violent take it by force."
T. Guthrie, The Parables in the Light of the Present Day,p. 126.
References: Luke 18:1-5. H.W. Beecher, Christian World Pulpit,vol. xx., p. 125; vol. xxxii., p. 214.Luke 18:1-8. Spurgeon, Sermons,vol. xv., No. 856; Homiletic Quarterly,vol. iii., p. 346; vol. xiii., p. 331; H. Calderwood, The Parables,p. 147; A. B. Bruce, The Training of the Twelve,p. 51; A. Murray, With Christ in the School of Prayer,p. 117; H. W. Beecher, Christian World Pulpit,vol. xxii., p. 7. Luke 18:1-14. Preacher's Monthly,vol. i., p. 382.