John C. Ryle’s excerpt

There are others of the Lord’s people who seem to be always getting on. They grow like the grass after rain. They increase like Israel in Egypt. They press on like Gideon, though sometimes “faint, yet always pursuing” (Judges 8:4). They are ever adding grace to grace, and faith to faith, and strength to strength. Every time you meet them their hearts seem larger, and their spiritual stature bigger, taller, and stronger. Every year they appear to see more, and know more, and believe more, and feel more in their religion. They not only have good works to prove the reality of their faith, but they are zealous of them. They not only do well, but they are unwearied in well-doing. (See Titus 2:14; Gal 6:9)

They attempt great things, and they do great things When they fail they try again, and when they fall they are soon up again. And all this time they think themselves poor unprofitable servants, and fancy they do nothing at all! These are those who make religion lovely and beautiful in the eyes of all. They wrest praise even from the unconverted, and win golden opinion even from the selfish men of the world. These are those whom it does one good to see, to be with, and to hear. When you meet them, you could believe that, like Moses, they had just come out from the presence of God.

Now, how can we account for the difference which I have just described? What is the reason that some believers are so much brighter and holier than others? I believe the difference, in nineteen cases out of twenty, arises from different habits about private prayer. I believe that those who are not eminently holy pray little, and those who are eminently holy pray much. Page 27 of PRAYER by John C. Ryle