When they entered from where their father had commanded them, it would not have availed them in the least against God, but it was out of a concern in Jacob's person. Since We have taught him, he had certain knowledge; but most people do not know.
Translation endnotes
[12:68] Perhaps, Jacob thought that a crowded group would pull the attention of officers or spies on the Egyptian border. Putting the eggs in different baskets is one of the ways of risk management.