When were the 430 years completed and where was Israel gathered?

The 430 years were completed when Moses led the children of Israel out of Egypt after another 215 years had passed. At that time the nation was gathered around Mount Sinai, at Exodus chapter 19, where God was preparing to do something totally different.

Les teaches that Jacob went down into Egypt because God told him not to fear and promised to make of him a great nation there. Jacob ended up in Egypt with all his sons, and they came out 215 years later with five, six, seven million souls. Another 215 years went by, making the 430 years complete, and Moses led the children of Israel out of Egypt. Les explains that the nation was gathered around Mount Sinai, and God was getting ready to do something totally different than He had ever done before. From Genesis 1 until Exodus 20, there were no written do's and don'ts from God regarding what men could and could not do, and there had been no God-instituted worship until this point. Les notes they probably brought sacrifices, but there had been no organized system of worship.

Exodus 19

What happened when the 430 years were completed and Israel gathered at Mount Sinai?

When the 430 years were completed and Israel gathered at Mount Sinai, God was preparing to do something totally different than He had ever done before: He would institute written commands and an organized system of worship, neither of which had existed from Genesis 1 until Exodus 20.