Lloyd-Jones writes,

Prayer should be going on throughout the day. Prayer need not of necessity be long; it can be brief, just an ejaculation at times is a true prayer. That is, surely. what the Apostle Paul means in his exhortation in 1 Thessalonians 5:17. "Pray without ceasing." . . . As you are walking along a road, or while you are working in your study, you turn frequently to God in prayer. (Preaching and Preachers, 170).

Paul Miller would agree: "We pray not out of discipline, but out of desperation."

In this 12-minute episode of Theology Refresh, Paul talks with David Mathis about the essence of prayer in the life of a pastor.