God desires to speak to His people through the Word of God. The Lord also desires that His people move by the Spirit of God and not by a feeling or by the mind. Likewise in evangelism, a Christian or a group of Christians must be led by the Holy Spirit in order to be effective.
Acts 13:3-5: And when they had fasted and prayed, and laid their hands on them, they sent them away. 4So they, being sent forth by the Holy Ghost, departed unto Seleucia; and from thence they sailed to Cyprus. 5And when they were at Salamis, they preached the word of God in the synagogues of the Jews: and they had also John to their minister.