Exodus 4:8 - Joseph Benson’s Commentary on the Old and New Testaments

The voice of the first sign The expression here is peculiarly proper and forcible; for God's works have a voice as well as his word, to which we ought diligently to attend. And these miracles spoke aloud in the ear of reason, and said, Believe in him whom God hath sent. Bishop Warburton observes here (see Divine Legation, book 4, sect. 4) that “in the first ages of the world, men being obliged to supply the deficiencies of language by significant signs, mutual converse was carried on by a mixed discourse of words and actions. Hence came the eastern phrase of the voice of the sign; and use and custom improving what had arisen out of necessity into ornament, this practice subsisted long after the necessity was over, especially in the East, the natural temperament of the people in that part of the world inclining them to a mode of conversation which exercised their vivacity by motion, and gratified it by a perpetual representation of material images.”