Do you not know how as you go about your ordinary round there is a constant undercurrent of thought?  You may be talking, or reading, or writing, or doing something more mechanical, and yet this underneath train of thought is running along apparently of its own accord, regardless of you.  It is broken at times, or you lose consciousness of it, as your work requires closer attention.  When you swing into the habitual things that you have done over and over again until they almost do themselves, it reasserts itself.

I remember years ago, in a banking-house where I served for a time, I had long additions to make.  Sometimes the rows of figures to be added up were a foot in length.  And I got so used to adding that often I was surprised to find that my thoughts had been far away, completely taken up with something else, while I had been adding the figures.  And fearing that I had been slighting my work, I would go back carefully all over the figures, only to find the footings correct.  The adding habit had become fixed, and left the undercurrent of my thought free.

That current is apt to reveal the heart’s purpose or set of mind.  Whatever you are most set upon, whatever your favorite fads or hobbies or inclinations or moods are, they are apt to appear in that involuntary train of thinking.  Now this can be cultivated.  It can be cultivated chiefly by the cultivation of the controlling purpose of your life, and then by trying to give directions to the undercurrent, and holding it to that direction.  If Jesus has gripped your heart the purpose of the life will be for Him.  And if you have come to realize the tremendous power of prayer, this undercurrent of thought can be made a prayer-current.

I do not mean by any forced or artificial holding of one’s self to such a current by dint of main force, and then mentally whipping yourself if you have forgotten.  The power of all action lies in its being perfectly free and natural.  You can cultivate the Jesus-passion, and the life-purpose, and the prayer-habit, and all of this will be a training of that undercurrent of thought toward prayer.

The shipping clerk, as he heads up his barrels and boxes, can be sending out and up his current of prayer.  At intervals he is thinking closely about something connected with his work.  Then his thoughts free themselves.  As he hammers in the nails, his thought says, “This is China day.”  Each ringing blow of the hammer rings out “This is China day:—­Thy blessing, Master, to-day upon the missionaries in Hang-chow;—­upon Mr. Blank out there;—­victory in Jesus’ name to-day;—­the physician missionaries, the nurses;—­Thy power upon them;—­help the native workers.”

The picture of his little prayer memorandum comes up before his mind’s eye.  The map of China stands out more or less distinctly, according to how long he may have been practising looking at it in his prayer-hour.  His mind runs of itself from one point to another.  And so, all the while, his undercurrent of praying goes on.  It is broken into by newer or more exacting duties; then free again, and swinging more or less to the thing his heart is set upon.  It becomes a perfectly free, natural thing with him.  This is part of the meaning of “Pray without ceasing.”