There is a subtle difference between 'insist on' and 'persist in'. 'Insist on' has a positive sense suggesting determination to do something or having others do something as in: Strict parents insist on their children doing their homework every evening. 'Persist in' indicates something negative as it suggests continuing to do something despite opposition or disapproval from outside as in: Although strict parents insist on their children doing their homework, many children persist in disobeying their parents and never do their homework.