Here is a excerpt his book The Possibilities of Prayer
THE ministry of prayer has been the peculiar distinction of all of God's saints. This has been the secret of their power. The energy and the soul of their work has been the closet. The need of help outside of man being so great, man's natural inability to always judge kindly, justly, and truly, and to act the Golden Rule, so prayer is enjoined by Christ to enable man to act in all these things according to the divine will. By prayer, the ability is secured to feel the law of love, to speak according to the law of love, and to do everything in harmony with the law of love.
God can help us. God is a father. We need God's good things to help us to "do justly, to love mercy, and to walk humbly before God." We need divine aid to act brotherly, wisely, and nobly, and to judge truly, and charitably. God's help to do all these things in God's way is secured by prayer. "Ask, and ye shall receive; seek, and ye shall find; knock, and it shall be opened unto you."
In the marvelous output of Christian graces and duties, the result of giving ourselves wholly to God, recorded in the twelfth chapter of Romans, we have the words, "Continuing instant in prayer," preceded by "rejoicing in hope, patient in tribulation," followed by, "Distributing to the necessity of the saints, given to hospitality." Paul thus writes as if these rich and rare graces and unselfish duties, so sweet, bright, generous, and unselfish, had for their center and source the ability to pray.
This is the same word which is used of the prayer of the disciples which ushered in Pentecost with all of its rich and glorious blessings of the Holy Spirit. In Colossians, Paul presses the word into the service of prayer again, "Continue in prayer, and watch in the same with thanksgiving." The word in its background and root means strong, the ability to stay, and persevere steadfast, to hold fast and firm, to give constant attention to.
In Acts, chapter six, it is translated, "Give ourselves continually to prayer." There is in it constancy, courage, unfainting perseverance. It means giving such marked attention to, and such deep concern to a thing, as will make it conspicuous and controlling.
This is an advance in demand on "continue." Prayer is to be incessant, without intermission, earnestly, no check in desire, in spirit or in act, the spirit and the life always in the attitude of prayer. The knees may not always be bent, the lips may not always be vocal with words of prayer, but the spirit is always in the act of prayer.
There ought to be no adjustment of life or spirit for closet hours. The closet spirit should sweetly rule and adjust all times and occasions. Our activities and work should be performed in the same spirit which makes our devotion and closet time sacred. "Without intermission, incessantly, earnestly," describes an opulence, and energy, and unabated and ceaseless strength and fullness of effort; like the full and exhaustless and spontaneous flow of an artesian stream. Touch the man of God who thus understands prayer, at any point, at any time, and a full current of prayer is seen flowing from him.
But all these untold benefits, of which the Holy Spirit is made to us the conveyor, go back in their disposition and results to prayer. Not on a little process and a mere performance of prayer is the coming of the Holy Spirit and of his great grace conditioned, but on prayer set on fire, by an unquenchable desire, with such a sense of need as cannot be denied, with a fixed determination which will not let go, and which will never faint till it wins the greatest good and gets the best and last blessing God has in store for us.
The first Christ, Jesus, our great high priest, forever blessed and adored be his name, was a gracious comforter, a faithful guide, a gifted teacher, a fearless advocate, a devoted friend, and an all-powerful intercessor. The other, "another comforter," the Holy Spirit, comes into all these blessed relations of fellowship, authority and aid, with all the tenderness, sweetness, fulness and efficiency of the first Christ.
Was the first Christ, the Christ of prayer? Did he offer prayers and supplications, with strong crying and tears unto God? Did he seek the silence, the solitude and the darkness that he might pray unheard and unwitnessed save by heaven, in his wrestling agony, for man with God? Does he ever live, enthroned above at the Father's right hand, there to pray for us?
Then how truly does the other Christ, the other comforter, the Holy Spirit, represent Jesus Christ as the Christ of prayer! This other Christ, the comforter, plants himself not in the waste of the mountain nor far into the night, but in the chill and the night of the human heart, to rouse it to the struggle, and to teach it the need and form of prayer. How the divine comforter, the spirit of truth, puts into the human heart the burden of earth's almighty need, and makes the human lips give voice to its mute and unutterable groanings!
What a mighty Christ of prayer is the Holy Spirit! How he quenches every flame in the heart but the flame of heavenly desire! How he quiets, like a weaned child, all the self-will, until in will, in brain, and in heart, and by mouth, we pray only as he prays. "Making intercession for the saints, according to the will of God." (HT)