Well, seeing that you asked, it would be my pleasure to explain

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The reason the first mention of the 10 commandments and the rest of the law is made AFTER the exodus from Egypt is simply this: before Jacob and his sons went to Egypt, they were part of the chosen therefore circumcised and they followed the decrees of God given to Adam and Eve and which then passed from generation to generation. God didn't need to write it down for them on stone, they complied. It was a given, because of who they were - The Chosen.
But when they were in Egypt they were exposed to the foreign gods and started to
proselytize to the foreign religion. Until they forgot their roots. They were in Egypt for over 300 years and as slaves. They didn't have their 'chosen' identity anymore. They had forgotten who they were. And God called them out of Egypt to TEACH them again who they were. And He did. It took Him 40 years in the desert to teach a new generation, but eventually He brought them through the desert and into the promised land. Again, to be the chosen nation! What a great promise this is for us! God dioes this for us too. He brings us through the 'desert" too. Sometimes it takes longer ... sometimes we learn quickly. But as the chosen, we too will be in the promised land.
And to answer your question on bringing gentiles out of Egypt: God brings me out of a spiritual Egypt on an almost daily basis! So, yes! The gentiles were brought out of "egypt" too - only it was a spiritual one!.
EXACTLY!!!! The ceremonial laws didn't have a purpose anymore after Jesus came to FULFILL it. It was only temporary (that why it was kept on the outside of the ark of the covenant and not on the inside)