Why did the people Israel say "we will do and obey" before even hearing the Ten Commandments? They should have said we will obey and do. What did they mean? What they actually said was, "We received these words from our fathers. If there is something new – tell us".
How so? "I am the Lord your God". They already believed in His unity, blessed be He, as is said, "and the people believed and obeyed". "Thou shalt have no other gods" – Abraham did not take part in his father Terah's idolatry. "Thou shalt not murder" – Abraham did not kill Isaac on the altar…"Thou shalt not commit adultery" – Joseph did not lie with his master's wife. "Thou shalt not steal" – Jacob did not steal from Laban's house during the twenty years he spent with him…"Thou shalt not bear false witness" – Joseph said, "For indeed I was stolen away out of the land of the Hebrews", and did not say, "I am the son of ministers and deputies". "Thou shalt not take [the name of the LORD thy God in vain]". Judah did not take an oath on the matter of Tamar and said, "She is more righteous than I". "Thou shalt not covet" – Isaac did not kick at his father's feet at the time of the Binding and extended respect to him…"Remember the Sabbath day, to keep it holy" – Joseph the Righteous already observed the Sabbath, as it says, "Slaughter an animal and prepare [a meal]", and they say that it was on a Friday.