The first true sign of spiritual life, prayer, is also the means of maintaining it. Man can as well live physically without breathing as spiritually without praying.
There is a class of animals, the cetaceous, neither fish nor sea-fowl, that inhabit the deep. It is their home; they never leave it for the shore; yet, though swimming beneath its waves and sounding its darkest depths, they have ever and anon to rise to the surface that they may breathe the air. Without that, these monarchs of the deep could not exist in the dense element in which they live, and move, and have their being.
And something like what is imposed on them by a physical necessity the Christian has to do by a spiritual one. It is by ever and anon ascending up to God, by rising through prayer into a loftier, purer region for supplies of divine grace, that he maintains his spiritual life.
Prevent these animals from rising to the surface, and they die for want of breath; prevent the Christian from rising to God, and he dies for want of prayer.