From The Ladder of Perfection by Walter Hilton (d. 1396):
The secret voice of Jesus is true, and it makes the soul true. There is no deception in it, nor pride, nor hypocrisy, but gentleness, peace, love and charity; it is full of life and grace. So when this voice speaks to a soul it may be so powerful that the soul puts aside what it is doing, whether it is praying, speaking, reading, thinking or working, and listen in rest and in love to the sweet sound of this spiritual voice. In this tranquility Jesus reveals himself to the soul. sometimes as a master to be feared, sometimes as a father to be respected and revered, and sometimes as a spouse to be loved. The soul becomes absorbed in a wonderful reverance that cannot be transcended. It feels secure and at deep rest, and desire only to remain in this state. It is in touch with the good of Jesus and by the grace of that touch it is made whole and safe, knowing Jesus alone. The only things it sees and feels are his goodness and favor.
This feeling can come without any special study of the Scriptures, and with few words at the mind’s disposal, although the soul may use words to express the feelings of the heart. Because of this gracious feeling the soul is separated from the love of the world or any thought of it; it takes no heed of it.
Grace may bring certain enlightenment to the soul which I call the voice of Jesus, for it is the intention of Jesus to make the soul his perfect spouse. Because this cannot be done suddenly, Jesus in the wisdom of his love uses many wonderful ways to unite himself with his chosen soul. He woos it as a lover, he shows it his wonders and gives it precious gifts, always promising more and showing deep affection and courtesy.