Isaiah 30:21

Thine ears shall hear a word; as oft as need requires thou shalt hear the voice of God's word and Spirit directing thee in thy course. Hear a word behind thee; a metaphor borrowed either,

1. From the custom of shepherds, who use to follow their sheep, and to recall them when they go out of the way. Or,

2. From travellers, who when they are gone out of the right way, are ofttimes recalled and admonished of their error by some other passenger or person who is behind them, and therefore discerns their mistake; which he could not so easily discover if he were before them.