ייִדישער מחשבֿה אויף הושע 2:4

At the time the ten commandments were given, the cherubs mounted on the holy ark were not included in the prohibition of reproductions of things in heaven or on earth, since up to the moment of their construction they were original, nothing like it had ever existed. Once they had been constructed however, the very fact of their existence made them subject to the prohibitions included in "do not make images." The reason G-d describes Himself as a "jealous HUSBAND," is to emphasize the husband/wife relationship. This explains the extreme patience G-d has demonstrated towards other nations serving idols. Only because Israel is related to Him by marital vows, does the "husband" display jealousy if He is cheated. The punishment that may extend to the fourth generation for those that hate G-d, i.e. who commit acts of idol worship of one form or another, is only the result of mercy. Were G-d to eliminate the aspect of mercy present in that kind of punishment, the second generation already would never have seen the light of day, since the generation guilty of idol worship would have been wiped out. The sin of the golden calf is a prime example. Had G-d wiped out the Jewish people at that time, the chances offered subsequent generations would have been lost then and there. On the other hand, reward for good conduct will be a factor as much as two thousand generations hence.