1. The sin that is here charged upon them—dissembling with God in their religious performances, v. 13. He that knows the heart, and cannot be imposed upon with shows and pretences, charges it upon them, whether their hearts condemn them for it or no. He that is greater than the heart, and knows all things, knows that though they draw nigh to him with their mouth, and honour him with their lips, yet they are not sincere worshippers. To worship God is to make our approaches to him, and to present our adorations of him; it is to draw nigh to him as those that have business with him, with an intention therein to honour him. This we are to do with our mouth and our lips, in speaking of him and in speaking to him; we must render to him the calves of our lips, Hosea xiv. 2. And, if the heart be full of his love and fear, out of the abundance of that the mouth will speak. But there are many whose religion is lip-labour only. They say that which expresses an approach to God and an adoration of him, but it is only from the teeth outward. For, (1.) They do not apply their minds to the service. When they pretend to be speaking to God they are thinking of a thousand impertinences: The have removed their hearts far from me, that they might not be employed in prayer, nor come within reach of the word. When work was to be done for God, which required the heart, that was sent out of the way on purpose, with the fool's eyes, into the ends of the earth. (2.) They do not make the word of God the rule of their worship, nor his will their reason: Their fear towards me is taught by the precept of men. They worshipped the God of Israel, not according to his appointment, but their own inventions, the directions of their false prophets or their idolatrous kings, or the usages of the nations that were round about them. The tradition of the elders was of more value and validity with them than the laws which God commanded Moses. Or, if they did worship God in a way conformable to his institution in the days of Hezekiah, a great reformer, they had more an eye to the precept of the king than to God's command. This our Saviour applies to the Jews in his time, who were formal in their devotions and wedded to their own inventions, and pronounces concerning them that in vain they did worship God, Matt. xv. 8, 9.