The sedra named after the father-in-law of Moses, Jethro, contains what are known as the decalogue or ten commandments.
One might ask which of the “10 words”, referred to by Moses in Hebrew as aseret hadevarim in Deuteronomy 5-13, is the most important? The first of the 10 words or commandments, which despite not being counted as one of the commandments by Christianity, because it is not really a commandment and because it identifies Hashem as having brought the children of Israel out of Egypt, is regarded by many Rabbis as the most important because Hashem provides the authority for the commandments. Without divine authority, they become a number of worthy principles. The reasoning that they show us how to behave often does not satisfy the younger generation.
One might also ask which is the second most important of these commandments. Rabbi Shlomo Riskin maintains that the one establishing a day of rest each week fills that role, because it implies that Hashem and not any other authority determines that humans are not slaves. They are free. Hashem is the G-d of freedom. One day of rest per week is regarded by many as Judaism’s greatest gift to the world.