According to dictionary.com, ethics are the rules of conduct recognized in respect to a particular class of human actions or a particular group, or culture. Worded another way, ethics are morals and values that govern a person's behavior.
I discussed morals and ethics in a previous post. In review, morals are the rules that differentiate right from wrong. A perfect example here are the Ten Commandments. Morals never change, and are handed down from generation to generation. Values are rules set by an individual person, and can be influenced by morals. Examples of values include Respect, Honor, Humility, Patriotism, Compassion, Honesty, Fairness, and Innovation.
Now let us define ethics.
Ethics: These are moral principles and values that govern a person's behavior. Since good ethics are essential to a productive society, it's essential to inculcate a good set of morals, and encourage a strong set of positive values.
So being ethical is following your morals and values, but it is also following the laws created by your society. People with the right morals and values are very likely to also follow the laws, which is why nearly every successful civilization has grown around some form of religion.
This was yet another reason that the founding fathers believed it was so important to make room for Christianity in the newly formed nation. It was the morals inculcated by the Church that they knew were important for creating the stable environment essential for a functioning society.
Since Christianity teaches the morals needed to encourage values needed for a functioning society, the founding fathers believed it was important to raise children under the influence of God and the Bible.
It worked, as the moral fabric of this nation was held firmly in place until the 1960s, when progressives started to succeed in changing American tradition.