Jeremiah 11:4

Which I commanded your fathers in the day that I brought them forth out of the land of Egypt, from the iron furnace, saying, Obey my voice, and do them, according to all which I command you: so shall ye be my people, and I will be your God:

In the day - i:e., when. The Sinaic covenant was some time after the exodus, but the two events are so connected as to be viewed as one.

Iron furnace - (; ). "Furnace" expresses the searching ordeal; "iron," the long duration of it. The furnace was of earth, not of iron (); a furnace in heat and duration enough to melt even iron. God's deliverance of them from such an ordeal of hard bondage in Egypt aggravates their present guilt.

Do them - namely, the words of the covenant ().

So shall ye be my people - (; , "If ye walk in my statutes, etc., I will walk among you, and will be your God, and ye shall be my people").