"Wherefore we labour . . . ." It is arduous work to keep the master ambition in front. It means holding one’s self to the high ideal year in and year out, not being ambitious to win souls or to establish churches or to have revivals, but being ambitious only to be "accepted of Him." It is not lack of spiritual experience that leads to failure, but lack of labouring to keep the ideal right. Once a week at least take stock before God and see whether you are keeping your life up to the standard He wishes. Paul is like a musician who does not heed the approval of the audience if he can catch the look of approval from his Master.
Any ambition which is in the tiniest degree away from this central one of being "approved unto God" may end in our being castaways. Learn to discern where the ambition leads, and you will see why it is so necessary to live facing the Lord Jesus Christ. Paul says – "Lest my body should make me take another line, I am constantly watching so that I may bring it into subjection and keep it under." (1 Cor. 9:27.)
I have to learn to relate everything to the master ambition, and to maintain it without any cessation. My worth to God in public is what I am in private. Is my master ambition to please Him and be acceptable to Him, or is it something less, no matter how noble?