"Many do not understand this union of the teaching of the Word and the guidance of the Spirit, so that there is a twofold difficulty in knowing what God's will may be. Some seek the will of God by an inner feeling or conviction and want the Spirit to lead them without the Word. Others seek His will in the Word without the living leading of the Holy Spirit. The two must be united--the Word and the Spirit--so that we can know the will of God and learn to pray according to it.
"The Word and the Spirit must be joined in our hearts. Only by their indwelling can we experience their teaching. The Word must abide in us. Our life must day by day be under its influence. Not from without but from within comes the quickening of the Word by the Spirit. Only he who yields himself entirely to the supremacy of the Word and the will of God can expect to discern what that will is and to boldly ask in prayer. He who through the Word and the Spirit lives in the will of God by doing it, will know to pray according to that will in the confidence that he hears us."
From Teach Me to Pray, Bethany House 2002, pages 202-03.