"The great living question has been before many: shall we really set ourselves to win back again the weapon of believing prayer which Satan has, in a measure, taken away from us?" It is indispensable that we be prepared to receive and obey all that we see to be according to the word and will of God. In The Prayer Life, Andrew Murray lays the path to dealing with the life of prayer and hidden fellowship with God. Murray believes that "Satan endeavors to become master of the Christian's inner chamber because he knows that if there has been unfaithfulness in prayer the testimony will bring but little loss to his kingdom." Spiritual power is derived from prayer, to strengthen our armor to better reflect the attacks of Satan we must practice and strengthen our prayer life. "A single word to the reader concerning the disposition of mind to which this book appeals! It is not enough that one should understand and appropriate the thought of the writer, and then rejoice because of the new insight he has obtained and the pleasure which knowledge has brought. There is something else which is of great importance. I must surrender myself to the truth so that I shall be ready, with an undivided will, immediately to perform all that I shall learn to be God's will." Andrew Murray was a South African writer, teacher, and Christian pastor. Murray considered missions to be "the chief end of the church." He was one of the founders of the South African General Mission (SAGM) later becoming the Africa Evangelical Fellowship (AEF) in 1965.