Abraham left Ur 1954 BC
Exodus 12:40-42 – “Now the time that the children of Israel dwelt in Egypt was four hundred and thirty years. And it came to pass at the end of four hundred and thirty years, even the selfsame day it came to pass, that all the hosts of Jehovah went out from the land of Egypt. It is a night to be much observed unto Jehovah for bringing them out from the land of Egypt: this is that night of Jehovah to be much observed of all the children of Israel throughout their generations.”
The 430-year sojourn of the Children of Israel included much of Abraham’s life and started when he first came to Canaan and would continue through the Egyptian captivity. The Exodus event from Egypt is also the first Passover. This date is April 16, 1524 BC (see Traditional Exodus Dates and Triangulating the Exodus to see how this was calculated).
By taking the morning of Saturday, 15 Nissan, 1524 BC, and subtracting 430 years from it, gives us 15 Nissan, 1954 BC, which, in our calendar, is April 28, 1954 BC.
On April 28, 1954 BC, Abraham left the sinful city of Ur. Then exactly 430 years later on Saturday, April 17, 1524 BC, the Children of Israel left Egypt on the first Passover. Both of these dates are the same because, by the Jews calendar, it is 15 Nissan. Our calendar makes it look like different dates, but the Israelite calendar is the same day.
Moses showed the similarities of their exit from sinful Egypt to the Promised Land with Abraham’s exit from the sinful city of Ur to pursue God’s promise. The paralleled plight built a link between Israel and their patriarch father, Abraham.