Many commentaries wonder why these 10 verses are treated specially. The questioner is correct! All of the commandments and all of the verses of the Torah have equal sanctity! Why the differentiation?
One explanation sees the 10 Commandments as being more than just commandments. They are the encapsulation of the entire Torah. The great Rabbi Saadya Gaon teaches that each of the 10 Commandments is, in truth, a category of Commandments. Thus, we are not standing for 10 commandments alone, we are standing for the entire Torah. This reading is like a reading of the entire Torah.
This makes sense in that each of the commandments seems to contain a number of sub- commandments. The second commanded, for example, seems to have four different elements: 1. You shall not have other gods, 2. You shall not make idols, 3. You shall not bow down to them, 4. You shall not serve them.
In fact, the phrase "10 Commandments," is mistranslated. It should be translated as, "10 utterances." Rabbi Saadya's explanation removes this problem.
Another explanation comes from Rabbi Moshe Nachmanidies. He compares the entire Sinai episode to the process of a convert to Judaism. The convert must accept the Torah and the commandments. The Talmud tells us that we don't need to teach the convert all 613 commandments in one shot. This would be very difficult. So what do we do?
Instead, we teach them a sampling of the commandments. We teach them easy ones, and harder ones. The same thing happened at Mount Sinai. God will reveal the full depth of the Torah over the years to come. At that moment when Israel "converted," and accepted the yoke of Judaism, they were taught a sampling of the commandments. Specifically, the 10 Commandments. Thus, perhaps we stand because we are accepting the Torah once more.
I would like to suggest another explanation. Rabbi Herschel Schechter of Yeshiva University explained the significance of the fifth commandment, "Honor thy father and my mother." According to a midrash, this commandment was actually given previously, at a place called "Marah."
Rabbi Schechter quotes from the work of Rabbi Joseph Engle, who wrote extensively on this commandment. After the Israelites encountered the bitter waters at Marah, the Torah tells us that, "There He gave [Israel] a decree and a law." What were the decree and the law?
Rashi explains that the decree was the commandments of the Red Heifer, which is called a decree in the book of numbers. The law refers to the body of civil laws. That all make sense. Where does the midrash see the commandment of honoring one's parents in this phrase?
Rabbi Engle brings an argument between the sages Hillel and Shammai as to whether it would've been better had man never been created. Their disciples debated this for years, and finally concluded that it would've been better had man indeed never been created. The commentary Tosaphot claims that this only applies to an average or sinful person. A righteous person, on the other hand, is certainly the beneficiary of being created.
So if a person is righteous, they should be grateful to their parents who brought them into this world. For them, honoring by father and mother is a logical law. The father and mother did them a favor.
If the person is not righteous, however, by rights they should be upset with their parents. Why did they bring them into this world and get them into this difficult situation? Nonetheless, honoring them remains a decree of God, even though it seems illogical. Thus, the commandment of honoring parents comes from both of those phrases: Decree, if the person is not righteous, and Law (a logical, understandable law), if the person is righteous.
I would like to suggest an additional explanation. The last commandment is the prohibition on coveting your neighbor's property. The Hasidic master, the Bnei Yissachar, expands this prohibition to include not buying a Alfa Romeo because your neighbor has an Alfa Romeo. Certainly it is prohibited to attempt to acquire your neighbor's. The desire to live your neighbor's life, that is what is wrong.
Therefore, a person who desires to live their neighbor's life will not properly fulfill honoring their parents. They will resent that they were not born to their neighbors parents, not given his skin, his talents, his successes. For this person, honoring the parents is a decree.
But a person who understands that they are unique, and that they have gifts that no one else has, is prepared to live their own life of excellence. For them, their parents are the best in the world. Honoring them is a logical law.
God gives a preamble to the 10 Commandments, explaining how the Jewish people shall be "chosen." Chosen means unique, not better or worse. It means different and special. Every human being should be different and special. Every nation should be different and special. The 10 Commandments teach us that. Be different, be special, be excellent, and you will change the world.