Andrew Murray 
The Prayer Life [EPUB ebook] 

There is the holy and most glorious God who invites us to come to him, to hold converse with him, to ask from him such things as we need, and to experience what a blessing there is in fellowship with him. He has created him we might find our highest glory and salvation. Without prayer, the helmet of salvation, and the shield of faith, and the sword of the Spirit which is God’s word, have no power. All depends on prayer. God teach us to believe and hold this fast!