The Bible speaks about this concept of unceasing prayer, to give some examples that seem to talk about thus:
1 Thessalonians 5:16-18 (Rejoice always, pray without ceasing, in everything give thanks; for this is the will of God in Christ Jesus for you.),
Mark 13:32-37; Matthew 26:40-41;
I've heard Eastern-Orthodox priests as having literal interpretation of this idea. Saying that we should follow the example of hermits, retreat in the wild and pray unceasingly.
I find that to be a bit extreme and wondered how do Lutherans, Reformed, Anglican and other mainline Protestants interpret these verses?