Because God did not reveal Himself in any physical form He forbade the Israelites' making any likeness of Him as an aid to worship (vv. 15-18). They were not to worship the heavenly bodies for this purpose either (v. 19) as did other ancient Near Easterners. Christians may not face the temptation to represent God in wood or stone, but we must be careful about thinking we can contain or limit Him or fully comprehend Him. Even though we have received much revelation about God we cannot fully grasp all there is to appreciate about Him.
Evidently the thought of God's bringing the Israelites out of Egypt, "the iron furnace,"to bring them into the land (v. 20) triggered Moses' reference to his own sin and its consequences (vv. 21-22).
"The use of metal by heating certain ores and then hammering the metallic residue or welding it to other parts while still hot may have appeared in the Near East in the first half of the third millennium B.C., but the manufacture of iron objects (usually weapons) was very limited till 1500 B.C. and later. Though the furnaces' of the OT world could not be heated sufficiently to make molten iron, artisans had learned to use bellows to make the hottest fire then known; and they knew that the hottest fire they could produce was necessary for their iron productions. Out of the iron-smelting furnace, out of Egypt' does not mean to imply that iron-smelting furnaces were in Egypt at that time. Rather, bringing Israel out of Egypt was like bringing her out of an iron-smelting furnace--the heavy bondage of Egypt with its accompanying difficulties and tensions being likened to the hottest fire then known."54
Israel was to learn from Moses' personal failure (v. 23) and be completely loyal to Yahweh.
"Not only can the inheritance be merited by obedience, but it can be lost by disobedience. Even Moses was excluded from the land of Canaan (i.e., the inheritance) because of his disobedience (Dt. 4:21-22). Clearly, Moses will be in heaven, but he forfeited his earthly inheritance. Not entering Canaan does not necessarily mean one is not born again.
"Even though Israel had become God's firstborn son (Ex. 4:22-23), the entire wilderness generation with the exception of Caleb and Joshua forfeited the inheritance due the firstborn. God disinherited them, and they wandered in the wilderness for forty years."55
The "consuming fire"metaphor refers to the manifestation of God's glory that burns in judgment all that is impure (cf. Exod. 24:17; Lev. 10:2; Num. 16:35; Heb. 12:29). God's jealousy is His zeal for righteousness that springs from His holiness. He would not tolerate Israel's allegiance to any other god. The connotation of pettiness that is present in the English word "jealousy"is totally absent from the Hebrew idea.
