Although preachers specifically are being referred to, the truth is equally applicable to Christians of all kinds.
(Christians) sent from God are not musical boxes, being once wound up, will play through their set tunes. They are trumpets which are utterly mute until the living breath causes them to give forth a certain sound.
(Taken from Lectures to My Students, p. 312-313).
How are you going about your day? Your week? Are you living as a musical box or a trumpet? Remember the words of Paul when he said, “Be filled with the Spirit” (Ephesians 5:18b). Every day, be filled with His Spirit so your life plays the melody of His salvation for all to hear.
A Pilgrim's Friend 