Most people assume that the listing of the Aseres Hadibros is in order of their importance. Starting with the recognition of G-d and finishing with the prohibition of coveting a friend’s possessions. Rav Shimshon Raphael Hirsch however suggests that the truth is actually the opposite.
The most important commandment was the last commandment, “you shall not covet your neighbour’s wife. Neither shall you desire your neighbour’s house, or field, or male or female slave, or ox, or donkey, or anything that belongs to your neighbour.” It seems rather preposterous to suggest however, that the last commandment is more important than the first, which is the acceptance of the heavenly yoke.
Rav Hirsch explains that the final commandment is the most vital because unfortunately in life there is a slippery slope. G-d commanded us not to covet our friend’s possessions, but what happens if we do? We eventually will bear false witness against our friends. What happens if we bear false witness against our friends? We will eventually steal. This slippery slope of events will continue until the eventual denial of the existence of G-d.
For this reason, says R’ Hirsch, the observance of the last commandment is just as important as the first one.