What are we specially taught by these words before me in the first commandment?

These words before me, or before my face, in the first commandment, teach us, that God, who seeth all things, taketh special notice of, and is much displeased with, the sin of having any other God: that so it may be an argument to dissuade from it, and to aggravate it as a most impudent provocation:[1] as also to persuade us to do as in his sight,: Whatever we do in his service.[2]

1. Ezek. 8:5-18

   Then he said to me, “Son of man, lift up your eyes now toward the north.” So I lifted up my eyes toward the north, and behold, north of the altar gate, in the entrance, was this image of jealousy. 6 And he said to me, “Son of man, do you see what they are doing, the great abominations that the house of Israel are committing here, to drive me far from my sanctuary? But you will see still greater abominations.”
   
   And he brought me to the entrance of the court, and when I looked, behold, there was a hole in the wall. Then he said to me, “Son of man, dig in the wall.” So I dug in the wall, and behold, there was an entrance. And he said to me, “Go in, and see the vile abominations that they are committing here.” So I went in and saw. And there, engraved on the wall all around, was every form of creeping things and loathsome beasts, and all the idols of the house of Israel. And before them stood seventy men of the elders of the house of Israel, with Jaazaniah the son of Shaphan standing among them. Each had his censer in his hand, and the smoke of the cloud of incense went up. Then he said to me, “Son of man, have you seen what the elders of the house of Israel are doing in the dark, each in his room of pictures? For they say, ‘The Lord does not see us, the Lord has forsaken the land.’” He said also to me, “You will see still greater abominations that they commit.”
   
   Then he brought me to the entrance of the north gate of the house of the Lord, and behold, there sat women weeping for Tammuz. Then he said to me, “Have you seen this, O son of man? You will see still greater abominations than these.”
   
   And he brought me into the inner court of the house of the Lord. And behold, at the entrance of the temple of the Lord, between the porch and the altar, were about twenty-five men, with their backs to the temple of the Lord, and their faces toward the east, worshiping the sun toward the east. Then he said to me, “Have you seen this, O son of man? Is it too light a thing for the house of Judah to commit the abominations that they commit here, that they should fill the land with violence and provoke me still further to anger? Behold, they put the branch to their nose. Therefore I will act in wrath. My eye will not spare, nor will I have pity. And though they cry in my ears with a loud voice, I will not hear them.”

2. Psa. 44:20-21

   If we had forgotten the name of our God or spread out our hands to a foreign god, would not God discover this? For he knows the secrets of the heart.

3. I Chr. 28:9 “

   And you, Solomon my son, know the God of your father and serve him with a whole heart and with a willing mind, for the Lord searches all hearts and understands every plan and thought. If you seek him, he will be found by you, but if you forsake him, he will cast you off forever.

Question 106, Westminster Larger Catechism