It was the privilege of Israel that they had not only a law in general sent them from heaven, once for all, to direct them into and keep them in the way of happiness, but that they had particular messages sent them from heaven, as there was occasion, for reproof, for correction, and for instruction in righteousness, when at any time they turned aside out of that way. Besides the written word which they had before them to read, they often heard a word behind them, saying, This is the way, Isa. xxx. 21. Here begins that way of God's dealing with them. When they would not hear Moses, let it be tried whether they will hear the prophets. In these verses we have a very awakening sermon that was preached to them when they began to cool in their religion.