In a parable, the Lord spoke of the need for constant prayer and of the avoidance of discouragement.
Do not fall into despondency if at times you do not get what you ask for. Keep up your courage. It will come later. For the Lord went on to tell another parable:
"If I do not fear God and have no reverence for man, yet since this woman affords me such pains I had better do her justice." (Luke 18:4-5)
The same thing will happen to those who cry out to God day and night-He will give them justice, and do it quickly. Take courage then, and persevere in your holy prayer with all sails unfurled.